Reduced exclusive lock durations

src/libs/services/auth/impl/AuthServiceBase.cpp

@@ -36,7 +36,7 @@ namespace Auth
 	AuthServiceBase::getOrCreateUser(std::string_view loginName)
 	{
 		Session& session {getDbSession()};
-		auto transaction {session.createUniqueTransaction()};
+		auto transaction {session.createWriteTransaction()};
 
 		User::pointer user {User::find(session, loginName)};
 		if (!user)
@@ -56,7 +56,7 @@ namespace Auth
 	AuthServiceBase::onUserAuthenticated(UserId userId)
 	{
 		Session& session {getDbSession()};
-		auto transaction {session.createUniqueTransaction()};
+		auto transaction {session.createWriteTransaction()};
 
 		User::pointer user {User::find(session, userId)};
 		if (user)

src/libs/services/auth/impl/AuthTokenService.cpp

@@ -54,7 +54,7 @@ namespace Auth
 
 		Database::Session& session {getDbSession()};
 
-		auto transaction {session.createUniqueTransaction()};
+		auto transaction {session.createWriteTransaction()};
 
 		Database::User::pointer user {Database::User::find(session, userId)};
 		if (!user)
@@ -76,7 +76,7 @@ namespace Auth
 		const std::string secretHash {sha1Function.compute(std::string {secret}, {})};
 
 		Database::Session& session {getDbSession()};
-		auto transaction {session.createUniqueTransaction()};
+		auto transaction {session.createWriteTransaction()};
 
 		Database::AuthToken::pointer authToken {Database::AuthToken::find(session, secretHash)};
 		if (!authToken)
@@ -131,7 +131,7 @@ namespace Auth
 	{
 		Database::Session& session {getDbSession()};
 
-		auto transaction {session.createUniqueTransaction()};
+		auto transaction {session.createWriteTransaction()};
 
 		Database::User::pointer user {Database::User::find(session, userId)};
 		if (!user)

src/libs/services/auth/impl/internal/InternalPasswordService.cpp

@@ -49,7 +49,7 @@ namespace Auth
 		Database::User::PasswordHash passwordHash;
 		{
 			Database::Session& session {getDbSession()};
-			auto transaction {session.createSharedTransaction()};
+			auto transaction {session.createReadTransaction()};
 
 			const Database::User::pointer user {Database::User::find(session, loginName)};
 			if (!user)
@@ -100,7 +100,7 @@ namespace Auth
 		const Database::User::PasswordHash passwordHash {hashPassword(newPassword)};
 
 		Database::Session& session {getDbSession()};
-		auto transaction {session.createUniqueTransaction()};
+		auto transaction {session.createWriteTransaction()};
 
 		Database::User::pointer user {Database::User::find(session, userId)};
 		if (!user)

src/libs/services/cover/impl/CoverService.cpp

@@ -51,7 +51,7 @@ namespace Cover
         {
             std::optional<TrackInfo> res;
 
-            auto transaction{ dbSession.createSharedTransaction() };
+            auto transaction{ dbSession.createReadTransaction() };
 
             const Database::Track::pointer track{ Database::Track::find(dbSession, trackId) };
             if (!track)
@@ -372,7 +372,7 @@ namespace Cover
         {
             std::optional<ReleaseInfo> res;
 
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             // get a track in this release, consider the release is in a single directory
             const auto tracks{ Track::find(session, Track::FindParameters {}.setRelease(releaseId).setRange(Range{ 0, 1 }).setSortMethod(TrackSortMethod::Release)) };

src/libs/services/database/CMakeLists.txt

@@ -17,6 +17,7 @@ add_library(lmsdatabase SHARED
 	impl/SqlQuery.cpp
 	impl/Track.cpp
 	impl/TrackBookmark.cpp
+	impl/TransactionChecker.cpp
 	impl/Types.cpp
 	impl/User.cpp
 	impl/Utils.cpp

src/libs/services/database/impl/Artist.cpp

@@ -38,7 +38,7 @@ namespace Database
         template <typename ResultType>
         Wt::Dbo::Query<ResultType> createQuery(Session& session, std::string_view itemToSelect, const Artist::FindParameters& params)
         {
-            session.checkSharedLocked();
+            session.checkReadTransaction();
 
             auto query{ session.getDboSession().query<ResultType>("SELECT DISTINCT " + std::string{ itemToSelect } + " FROM artist a") };
             if (params.sortMethod == ArtistSortMethod::LastWritten
@@ -175,14 +175,14 @@ namespace Database
 
     std::size_t Artist::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM artist");
     }
 
     std::vector<Artist::pointer> Artist::find(Session& session, const std::string& name)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         Wt::Dbo::collection<Wt::Dbo::ptr<Artist>> res = session.getDboSession().find<Artist>()
             .where("name = ?").bind(std::string{ name, 0, _maxNameLength })
@@ -193,33 +193,33 @@ namespace Database
 
     Artist::pointer Artist::find(Session& session, const UUID& mbid)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<Artist>().where("mbid = ?").bind(std::string{ mbid.getAsString() }).resultValue();
     }
 
     Artist::pointer Artist::find(Session& session, ArtistId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<Artist>().where("id = ?").bind(id).resultValue();
     }
 
     bool Artist::exists(Session& session, ArtistId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().query<int>("SELECT 1 FROM artist").where("id = ?").bind(id).resultValue() == 1;
     }
 
 
     RangeResults<ArtistId> Artist::findOrphanIds(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ session.getDboSession().query<ArtistId>("SELECT DISTINCT a.id FROM artist a WHERE NOT EXISTS(SELECT 1 FROM track t INNER JOIN track_artist_link t_a_l ON t_a_l.artist_id = a.id WHERE t.id = t_a_l.track_id)") };
         return Utils::execQuery<ArtistId>(query, range);
     }
 
     RangeResults<ArtistId> Artist::findIds(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery<ArtistId>(session, params) };
         return Utils::execQuery<ArtistId>(query, params.range);
@@ -227,7 +227,7 @@ namespace Database
 
     RangeResults<Artist::pointer> Artist::find(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery<Wt::Dbo::ptr<Artist>>(session, params) };
         return Utils::execQuery<Artist::pointer>(query, params.range);
@@ -235,7 +235,7 @@ namespace Database
 
     void Artist::find(Session& session, const FindParameters& params, std::function<void(const pointer&)> func)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery<Wt::Dbo::ptr<Artist>>(session, params) };
         Utils::execQuery(query, params.range, func);

src/libs/services/database/impl/AuthToken.cpp

@@ -44,7 +44,7 @@ namespace Database
 	void
 	AuthToken::removeExpiredTokens(Session& session, const Wt::WDateTime& now)
 	{
-		session.checkUniqueLocked();
+		session.checkWriteTransaction();
 
 		session.getDboSession().execute("DELETE FROM auth_token WHERE expiry < ?").bind(now);
 	}
@@ -52,7 +52,7 @@ namespace Database
 	AuthToken::pointer
 	AuthToken::find(Session& session, std::string_view value)
 	{
-		session.checkSharedLocked();
+		session.checkReadTransaction();
 
 		return session.getDboSession().find<AuthToken>()
 			.where("value = ?").bind(value)

src/libs/services/database/impl/Cluster.cpp

@@ -35,7 +35,7 @@ namespace Database
         template <typename ResultType>
         Wt::Dbo::Query<ResultType> createQuery(Session& session, std::string_view itemToSelect, const Cluster::FindParameters& params)
         {
-            session.checkSharedLocked();
+            session.checkReadTransaction();
 
             auto query{ session.getDboSession().query<ResultType>("SELECT DISTINCT " + std::string{ itemToSelect } + " FROM cluster c") };
 
@@ -85,14 +85,14 @@ namespace Database
 
     std::size_t Cluster::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM cluster");
     }
 
    RangeResults<ClusterId> Cluster::findIds(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ createQuery<ClusterId>(session, params) };
 
         return Utils::execQuery<ClusterId>(query, params.range);
@@ -100,7 +100,7 @@ namespace Database
 
     RangeResults<Cluster::pointer> Cluster::find(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ createQuery<Wt::Dbo::ptr<Cluster>>(session, params) };
 
         return Utils::execQuery<Cluster::pointer>(query, params.range);
@@ -108,7 +108,7 @@ namespace Database
 
     RangeResults<ClusterId> Cluster::findOrphans(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ session.getDboSession().query<ClusterId>("SELECT DISTINCT c.id FROM cluster c WHERE NOT EXISTS(SELECT 1 FROM track_cluster t_c WHERE t_c.cluster_id = c.id)") };
 
         return Utils::execQuery<ClusterId>(query, range);
@@ -116,14 +116,14 @@ namespace Database
 
     Cluster::pointer Cluster::find(Session& session, ClusterId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<Cluster>().where("id = ?").bind(id).resultValue();
     }
 
     std::size_t Cluster::computeTrackCount(Session& session, ClusterId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(t.id) FROM track t INNER JOIN track_cluster t_c ON t_c.track_id = t.id")
             .where("t_c.cluster_id = ?").bind(id).resultValue();
@@ -131,7 +131,7 @@ namespace Database
 
     std::size_t Cluster::computeReleaseCount(Session& session, ClusterId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(DISTINCT r.id) FROM release r INNER JOIN track t on t.release_id = r.id INNER JOIN track_cluster t_c ON t_c.track_id = t.id")
             .where("t_c.cluster_id = ?").bind(id).resultValue();
@@ -164,7 +164,7 @@ namespace Database
 
     std::size_t ClusterType::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM cluster_type");
     }
@@ -172,7 +172,7 @@ namespace Database
 
     RangeResults<ClusterTypeId> ClusterType::findOrphans(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<ClusterTypeId>(
                 "SELECT c_t.id from cluster_type c_t"
@@ -184,7 +184,7 @@ namespace Database
 
     RangeResults<ClusterTypeId> ClusterType::findUsed(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<ClusterTypeId>(
                 "SELECT DISTINCT c_t.id from cluster_type c_t")
@@ -195,21 +195,21 @@ namespace Database
 
     ClusterType::pointer ClusterType::find(Session& session, std::string_view name)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<ClusterType>().where("name = ?").bind(std::string{ name }).resultValue();
     }
 
     ClusterType::pointer ClusterType::find(Session& session, ClusterTypeId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<ClusterType>().where("id = ?").bind(id).resultValue();
     }
 
     RangeResults<ClusterTypeId> ClusterType::find(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<ClusterTypeId>("SELECT id from cluster_type") };
 

src/libs/services/database/impl/Listen.cpp

@@ -140,25 +140,25 @@ namespace Database
 
     Listen::pointer Listen::create(Session& session, ObjectPtr<User> user, ObjectPtr<Track> track, ScrobblingBackend backend, const Wt::WDateTime& dateTime)
     {
-        session.checkUniqueLocked();
+        session.checkWriteTransaction();
         return session.getDboSession().add(std::unique_ptr<Listen> {new Listen{ user, track, backend, dateTime }});
     }
 
     std::size_t Listen::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM listen");
     }
 
     Listen::pointer Listen::find(Session& session, ListenId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<Listen>().where("id = ?").bind(id).resultValue();
     }
 
     RangeResults<ListenId> Listen::find(Session& session, const FindParameters& parameters)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<ListenId>("SELECT id FROM listen")
                                 .orderBy("date_time") };
@@ -177,7 +177,7 @@ namespace Database
 
     Listen::pointer Listen::find(Session& session, UserId userId, TrackId trackId, ScrobblingBackend backend, const Wt::WDateTime& dateTime)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<Listen>()
             .where("user_id = ?").bind(userId)
@@ -189,7 +189,7 @@ namespace Database
 
     RangeResults<ArtistId> Listen::getTopArtists(Session& session, UserId userId, ScrobblingBackend backend, const std::vector<ClusterId>& clusterIds, std::optional<TrackArtistLinkType> linkType, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ createArtistsQuery(session.getDboSession(), userId, backend, clusterIds, linkType) };
 
         auto collection{ query
@@ -201,7 +201,7 @@ namespace Database
 
     RangeResults<ReleaseId> Listen::getTopReleases(Session& session, UserId userId, ScrobblingBackend backend, const std::vector<ClusterId>& clusterIds, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ createReleasesQuery(session.getDboSession(), userId, backend, clusterIds)
                         .orderBy("COUNT(r.id) DESC")
                         .groupBy("r.id") };
@@ -211,7 +211,7 @@ namespace Database
 
     RangeResults<TrackId> Listen::getTopTracks(Session& session, UserId userId, ScrobblingBackend backend, const std::vector<ClusterId>& clusterIds, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ createTracksQuery(session.getDboSession(), userId, backend, clusterIds)
                         .orderBy("COUNT(t.id) DESC")
                         .groupBy("t.id") };
@@ -221,7 +221,7 @@ namespace Database
 
     RangeResults<ArtistId> Listen::getRecentArtists(Session& session, UserId userId, ScrobblingBackend backend, const std::vector<ClusterId>& clusterIds, std::optional<TrackArtistLinkType> linkType, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ createArtistsQuery(session.getDboSession(), userId, backend, clusterIds, linkType)
                         .groupBy("a.id").having("l.date_time = MAX(l.date_time)")
                         .orderBy("l.date_time DESC") };
@@ -231,7 +231,7 @@ namespace Database
 
     RangeResults<ReleaseId> Listen::getRecentReleases(Session& session, UserId userId, ScrobblingBackend backend, const std::vector<ClusterId>& clusterIds, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ createReleasesQuery(session.getDboSession(), userId, backend, clusterIds)
                         .groupBy("r.id").having("l.date_time = MAX(l.date_time)")
                         .orderBy("l.date_time DESC") };
@@ -241,7 +241,7 @@ namespace Database
 
     RangeResults<TrackId> Listen::getRecentTracks(Session& session, UserId userId, ScrobblingBackend backend, const std::vector<ClusterId>& clusterIds, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         auto query{ createTracksQuery(session.getDboSession(), userId, backend, clusterIds)
                         .groupBy("t.id").having("l.date_time = MAX(l.date_time)")
                         .orderBy("l.date_time DESC") };
@@ -251,7 +251,7 @@ namespace Database
 
     std::size_t Listen::getCount(Session& session, UserId userId, ScrobblingBackend backend, TrackId trackId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) from listen l")
             .where("l.track_id = ?").bind(trackId)
@@ -262,7 +262,7 @@ namespace Database
 
     std::size_t Listen::getCount(Session& session, UserId userId, ScrobblingBackend backend, ReleaseId releaseId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT IFNULL(MIN(count_result), 0)"
             " FROM ("
@@ -279,7 +279,7 @@ namespace Database
 
     Listen::pointer Listen::getMostRecentListen(Session& session, UserId userId, ScrobblingBackend backend, ReleaseId releaseId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         // TODO not pending remove?
         return session.getDboSession().query<Wt::Dbo::ptr<Listen>>("SELECT l from listen l")
@@ -294,7 +294,7 @@ namespace Database
 
     Listen::pointer Listen::getMostRecentListen(Session& session, UserId userId, ScrobblingBackend backend, TrackId trackId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         // TODO not pending remove?
         return session.getDboSession().query<Wt::Dbo::ptr<Listen>>("SELECT l from listen l")
             .where("l.track_id = ?").bind(trackId)

src/libs/services/database/impl/Migration.cpp

@@ -32,7 +32,7 @@ namespace Database
 {
     VersionInfo::pointer VersionInfo::getOrCreate(Session& session)
     {
-        session.checkUniqueLocked();
+        session.checkWriteTransaction();
 
         pointer versionInfo{ session.getDboSession().find<VersionInfo>() };
         if (!versionInfo)
@@ -43,7 +43,7 @@ namespace Database
 
     VersionInfo::pointer VersionInfo::get(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<VersionInfo>();
     }
@@ -276,7 +276,7 @@ CREATE TABLE IF NOT EXISTS "track_backup" (
         };
 
         {
-            auto uniqueTransaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             Version version;
             try

src/libs/services/database/impl/Release.cpp

@@ -198,7 +198,7 @@ namespace Database
 
     std::vector<Release::pointer> Release::find(Session& session, const std::string& name)
     {
-        session.checkUniqueLocked();
+        session.checkWriteTransaction();
 
         auto res{ session.getDboSession()
                             .find<Release>()
@@ -210,7 +210,7 @@ namespace Database
 
     Release::pointer Release::find(Session& session, const UUID& mbid)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession()
             .find<Release>()
@@ -220,7 +220,7 @@ namespace Database
 
     Release::pointer Release::find(Session& session, ReleaseId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession()
             .find<Release>()
@@ -230,20 +230,20 @@ namespace Database
 
     bool Release::exists(Session& session, ReleaseId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().query<int>("SELECT 1 FROM release").where("id = ?").bind(id).resultValue() == 1;
     }
 
     std::size_t Release::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM release");
     }
 
     RangeResults<ReleaseId> Release::findIdsOrderedByArtist(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         // TODO merge with find
         auto query{ session.getDboSession().query<ReleaseId>(
@@ -258,7 +258,7 @@ namespace Database
 
     RangeResults<ReleaseId> Release::findOrphanIds(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<ReleaseId>("select r.id from release r LEFT OUTER JOIN Track t ON r.id = t.release_id WHERE t.id IS NULL") };
         return Utils::execQuery<ReleaseId>(query, range);
@@ -266,7 +266,7 @@ namespace Database
 
     RangeResults<Release::pointer> Release::find(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery<Wt::Dbo::ptr<Release>>(session, "DISTINCT r", params) };
         return Utils::execQuery<pointer>(query, params.range);
@@ -274,7 +274,7 @@ namespace Database
 
     void Release::find(Session& session, const FindParameters& params, std::function<void(const pointer&)> func)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery<Wt::Dbo::ptr<Release>>(session, "DISTINCT r", params) };
         Utils::execQuery<pointer>(query, params.range, func);
@@ -282,7 +282,7 @@ namespace Database
 
     RangeResults<ReleaseId> Release::findIds(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery<ReleaseId>(session, "DISTINCT r.id", params) };
         return Utils::execQuery<ReleaseId>(query, params.range);
@@ -290,7 +290,7 @@ namespace Database
 
     std::size_t Release::getCount(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return createQuery<int>(session, "COUNT(DISTINCT r.id)", params).resultValue();
     }

src/libs/services/database/impl/ScanSettings.cpp

@@ -45,7 +45,7 @@ namespace Database {
 void
 ScanSettings::init(Session& session)
 {
-	session.checkUniqueLocked();
+	session.checkWriteTransaction();
 
 	pointer settings {get(session)};
 	if (settings)
@@ -58,7 +58,7 @@ ScanSettings::init(Session& session)
 ScanSettings::pointer
 ScanSettings::get(Session& session)
 {
-	session.checkSharedLocked();
+	session.checkReadTransaction();
 
 	return session.getDboSession().find<ScanSettings>().resultValue();
 }
@@ -109,7 +109,7 @@ std::set<std::string> getNames(It begin, It end)
 void
 ScanSettings::setClusterTypes(Session& session, const std::set<std::string>& clusterTypeNames)
 {
-	session.checkUniqueLocked();
+	session.checkWriteTransaction();
 
 	bool needRescan {};
 

src/libs/services/database/impl/Session.cpp

@@ -39,6 +39,7 @@
 #include "services/database/TrackArtistLink.hpp"
 #include "services/database/TrackList.hpp"
 #include "services/database/TrackFeatures.hpp"
+#include "services/database/TransactionChecker.hpp"
 #include "services/database/User.hpp"
 #include "EnumSetTraits.hpp"
 #include "Migration.hpp"
@@ -46,6 +47,29 @@
 namespace Database
 {
 
+    WriteTransaction::WriteTransaction(RecursiveSharedMutex& mutex, Wt::Dbo::Session& session)
+        : _lock{ mutex },
+        _transaction{ session }
+    {
+        TransactionChecker::pushWriteTransaction(_transaction.session());
+    }
+
+    WriteTransaction::~WriteTransaction()
+    {
+        TransactionChecker::popWriteTransaction(_transaction.session());
+    }
+
+    ReadTransaction::ReadTransaction(Wt::Dbo::Session& session)
+        : _transaction{ session }
+    {
+        TransactionChecker::pushReadTransaction(_transaction.session());
+    }
+
+    ReadTransaction::~ReadTransaction()
+    {
+        TransactionChecker::popReadTransaction(_transaction.session());
+    }
+
     Session::Session(Db& db)
         : _db{ db }
     {
@@ -71,36 +95,14 @@ namespace Database
         _session.mapClass<User>("user");
     }
 
-    UniqueTransaction::UniqueTransaction(RecursiveSharedMutex& mutex, Wt::Dbo::Session& session)
+    WriteTransaction Session::createWriteTransaction()
-        : _lock{ mutex },
-        _transaction{ session }
     {
+        return WriteTransaction{ _db.getMutex(), _session };
     }
 
-    SharedTransaction::SharedTransaction(RecursiveSharedMutex& mutex, Wt::Dbo::Session& session)
+    ReadTransaction Session::createReadTransaction()
-        : _lock{ mutex },
-        _transaction{ session }
     {
-    }
+        return ReadTransaction{ _session };
-
-    void Session::checkUniqueLocked()
-    {
-        assert(_db.getMutex().isUniqueLocked());
-    }
-
-    void Session::checkSharedLocked()
-    {
-        assert(_db.getMutex().isSharedLocked());
-    }
-
-    UniqueTransaction Session::createUniqueTransaction()
-    {
-        return UniqueTransaction{ _db.getMutex(), _session };
-    }
-
-    SharedTransaction Session::createSharedTransaction()
-    {
-        return SharedTransaction{ _db.getMutex(), _session };
     }
 
     void Session::prepareTables()
@@ -127,7 +129,7 @@ namespace Database
 
         // Indexes
         {
-            auto uniqueTransaction{ createUniqueTransaction() };
+            auto transaction{ createWriteTransaction() };
             _session.execute("CREATE INDEX IF NOT EXISTS artist_name_idx ON artist(name)");
             _session.execute("CREATE INDEX IF NOT EXISTS artist_sort_name_nocase_idx ON artist(sort_name COLLATE NOCASE)");
             _session.execute("CREATE INDEX IF NOT EXISTS artist_mbid_idx ON artist(mbid)");
@@ -172,7 +174,7 @@ namespace Database
 
         // Initial settings tables
         {
-            auto uniqueTransaction{ createUniqueTransaction() };
+            auto uniqueTransaction{ createWriteTransaction() };
 
             ScanSettings::init(*this);
         }
@@ -182,7 +184,7 @@ namespace Database
     {
         LMS_LOG(DB, INFO) << "Analyzing database...";
         {
-            auto uniqueTransaction{ createUniqueTransaction() };
+            auto transaction{ createWriteTransaction() };
             _session.execute("ANALYZE");
         }
         LMS_LOG(DB, INFO) << "Database Analyze complete";
@@ -192,7 +194,7 @@ namespace Database
     {
         LMS_LOG(DB, INFO) << "Optimizing database...";
         {
-            auto uniqueTransaction{ createUniqueTransaction() };
+            auto transaction{ createWriteTransaction() };
             _session.execute("PRAGMA optimize");
         }
         LMS_LOG(DB, INFO) << "Database optimizing complete";

src/libs/services/database/impl/StarredArtist.cpp

@@ -43,19 +43,19 @@ namespace Database
 
     std::size_t StarredArtist::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM starred_artist");
     }
 
     StarredArtist::pointer StarredArtist::find(Session& session, StarredArtistId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<StarredArtist>().where("id = ?").bind(id).resultValue();
     }
 
     StarredArtist::pointer StarredArtist::find(Session& session, ArtistId artistId, UserId userId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().query<Wt::Dbo::ptr<StarredArtist>>("SELECT s_a from starred_artist s_a")
             .join("user u ON u.id = s_a.user_id")
             .where("s_a.artist_id = ?").bind(artistId)
@@ -66,7 +66,7 @@ namespace Database
 
     StarredArtist::pointer StarredArtist::find(Session& session, ArtistId artistId, UserId userId, FeedbackBackend backend)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<StarredArtist>()
             .where("artist_id = ?").bind(artistId)
             .where("user_id = ?").bind(userId)

src/libs/services/database/impl/StarredRelease.cpp

@@ -43,19 +43,19 @@ namespace Database
 
     std::size_t StarredRelease::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM starred_release");
     }
 
     StarredRelease::pointer StarredRelease::find(Session& session, StarredReleaseId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<StarredRelease>().where("id = ?").bind(id).resultValue();
     }
 
     StarredRelease::pointer StarredRelease::find(Session& session, ReleaseId releaseId, UserId userId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().query<Wt::Dbo::ptr<StarredRelease>>("SELECT s_r from starred_release s_r")
             .join("user u ON u.id = s_r.user_id")
             .where("s_r.release_id = ?").bind(releaseId)
@@ -66,7 +66,7 @@ namespace Database
 
     StarredRelease::pointer StarredRelease::find(Session& session, ReleaseId releaseId, UserId userId, FeedbackBackend backend)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<StarredRelease>()
             .where("release_id = ?").bind(releaseId)
             .where("user_id = ?").bind(userId)

src/libs/services/database/impl/StarredTrack.cpp

@@ -43,19 +43,19 @@ namespace Database
 
     std::size_t StarredTrack::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM starred_track");
     }
 
     StarredTrack::pointer StarredTrack::find(Session& session, StarredTrackId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<StarredTrack>().where("id = ?").bind(id).resultValue();
     }
 
     StarredTrack::pointer StarredTrack::find(Session& session, TrackId trackId, UserId userId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().query<Wt::Dbo::ptr<StarredTrack>>("SELECT s_t from starred_track s_t")
             .join("user u ON u.id = s_t.user_id")
             .where("s_t.track_id = ?").bind(trackId)
@@ -66,7 +66,7 @@ namespace Database
 
     StarredTrack::pointer StarredTrack::find(Session& session, TrackId trackId, UserId userId, FeedbackBackend backend)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<StarredTrack>()
             .where("track_id = ?").bind(trackId)
             .where("user_id = ?").bind(userId)
@@ -85,7 +85,7 @@ namespace Database
 
     RangeResults<StarredTrackId> StarredTrack::find(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<StarredTrackId>("SELECT DISTINCT s_t.id FROM starred_track s_t") };
 

src/libs/services/database/impl/Track.cpp

@@ -42,7 +42,7 @@ namespace Database
         template <typename ResultType>
         Wt::Dbo::Query<ResultType> createQuery(Session& session, std::string_view itemToSelect, const Track::FindParameters& params)
         {
-            session.checkSharedLocked();
+            session.checkReadTransaction();
 
             std::string selectStatement{ params.distinct ? "SELECT DISTINCT" : "SELECT" };
             auto query{ session.getDboSession().query<ResultType>(selectStatement + " " + std::string{ itemToSelect } + " FROM track t") };
@@ -200,21 +200,21 @@ namespace Database
     std::size_t
         Track::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM track");
     }
 
     Track::pointer Track::findByPath(Session& session, const std::filesystem::path& p)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<Track>().where("file_path = ?").bind(p.string()).resultValue();
     }
 
     Track::pointer Track::find(Session& session, TrackId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<Track>()
             .where("id = ?").bind(id)
@@ -223,14 +223,14 @@ namespace Database
 
     bool Track::exists(Session& session, TrackId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT 1 from track").where("id = ?").bind(id).resultValue() == 1;
     }
 
     std::vector<Track::pointer> Track::findByMBID(Session& session, const UUID& mbid)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto res{ session.getDboSession().find<Track>()
             .where("mbid = ?").bind(std::string {mbid.getAsString()})
@@ -241,7 +241,7 @@ namespace Database
 
     std::vector<Track::pointer> Track::findByRecordingMBID(Session& session, const UUID& mbid)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto res{ session.getDboSession().find<Track>()
             .where("recording_mbid = ?").bind(std::string {mbid.getAsString()})
@@ -253,7 +253,7 @@ namespace Database
     RangeResults<Track::PathResult> Track::findPaths(Session& session, std::optional<Range> range)
     {
         using QueryResultType = std::tuple<TrackId, std::string>;
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         // TODO Dbo traits on filesystem
         auto query{ session.getDboSession().query<QueryResultType>("SELECT id, file_path FROM track") };
@@ -276,7 +276,7 @@ namespace Database
 
     RangeResults<TrackId> Track::findIdsTrackMBIDDuplicates(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<TrackId>("SELECT track.id FROM track WHERE mbid in (SELECT mbid FROM track WHERE mbid <> '' GROUP BY mbid HAVING COUNT (*) > 1)")
             .orderBy("track.release_id,track.disc_number,track.track_number,track.mbid") };
@@ -286,7 +286,7 @@ namespace Database
 
     RangeResults<TrackId> Track::findIdsWithRecordingMBIDAndMissingFeatures(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<TrackId>("SELECT t.id FROM track t")
             .where("LENGTH(t.recording_mbid) > 0")
@@ -314,7 +314,7 @@ namespace Database
 
     RangeResults<TrackId> Track::findIds(Session& session, const FindParameters& parameters)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery<TrackId>(session, parameters) };
         return Utils::execQuery<TrackId>(query, parameters.range);
@@ -322,7 +322,7 @@ namespace Database
 
     RangeResults<Track::pointer> Track::find(Session& session, const FindParameters& parameters)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery<Wt::Dbo::ptr<Track>>(session, parameters) };
         return Utils::execQuery<Track::pointer>(query, parameters.range);
@@ -330,7 +330,7 @@ namespace Database
 
     void Track::find(Session& session, const FindParameters& params, std::function<void(const Track::pointer&)> func)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery<Wt::Dbo::ptr<Track>>(session, params)};
         Utils::execQuery(query, params.range, func);
@@ -339,7 +339,7 @@ namespace Database
     RangeResults<TrackId> Track::findSimilarTrackIds(Session& session, const std::vector<TrackId>& tracks, std::optional<Range> range)
     {
         assert(!tracks.empty());
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         std::ostringstream oss;
         for (std::size_t i{}; i < tracks.size(); ++i)
@@ -524,7 +524,7 @@ namespace Database
     {
         std::ostream& operator<<(std::ostream& os, const TrackInfo& trackInfo)
         {
-            auto transaction{ trackInfo.session.createSharedTransaction() };
+            auto transaction{ trackInfo.session.createReadTransaction() };
 
             const Track::pointer track{ Track::find(trackInfo.session, trackInfo.trackId) };
             if (track)

src/libs/services/database/impl/TrackArtistLink.cpp

@@ -32,7 +32,7 @@ namespace Database
     {
         Wt::Dbo::Query<TrackArtistLinkId> createQuery(Session& session, const TrackArtistLink::FindParameters& params)
         {
-            session.checkSharedLocked();
+            session.checkReadTransaction();
 
             auto query{ session.getDboSession().query<TrackArtistLinkId>("SELECT DISTINCT t_a_l.id FROM track_artist_link t_a_l") };
 
@@ -65,7 +65,7 @@ namespace Database
 
     TrackArtistLink::pointer TrackArtistLink::create(Session& session, ObjectPtr<Track> track, ObjectPtr<Artist> artist, TrackArtistLinkType type, std::string_view subType)
     {
-        session.checkUniqueLocked();
+        session.checkWriteTransaction();
 
         TrackArtistLink::pointer res{ session.getDboSession().add(std::make_unique<TrackArtistLink>(track, artist, type, subType)) };
         session.getDboSession().flush();
@@ -75,13 +75,13 @@ namespace Database
 
     TrackArtistLink::pointer TrackArtistLink::find(Session& session, TrackArtistLinkId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         return session.getDboSession().find<TrackArtistLink>().where("id = ?").bind(id).resultValue();
     }
 
     RangeResults<TrackArtistLinkId> TrackArtistLink::find(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ createQuery(session, params) };
         return Utils::execQuery<TrackArtistLinkId>(query, params.range);
@@ -89,7 +89,7 @@ namespace Database
 
     EnumSet<TrackArtistLinkType> TrackArtistLink::findUsedTypes(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto res{ session.getDboSession().query<TrackArtistLinkType>("SELECT DISTINCT type from track_artist_link").resultList() };
 
@@ -98,7 +98,7 @@ namespace Database
 
     EnumSet<TrackArtistLinkType> TrackArtistLink::findUsedTypes(Session& session, ArtistId artistId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto res{ session.getDboSession()
             .query<TrackArtistLinkType>("SELECT DISTINCT type from track_artist_link")

src/libs/services/database/impl/TrackBookmark.cpp

@@ -40,14 +40,14 @@ namespace Database {
 
     std::size_t TrackBookmark::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM track_bookmark");
     }
 
     RangeResults<TrackBookmarkId> TrackBookmark::find(Session& session, UserId userId, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<TrackBookmarkId>("SELECT id from track_bookmark")
                     .where("user_id = ?").bind(userId) };
@@ -57,7 +57,7 @@ namespace Database {
 
     TrackBookmark::pointer TrackBookmark::find(Session& session, UserId userId, TrackId trackId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<TrackBookmark>()
             .where("user_id = ?").bind(userId)
@@ -67,7 +67,7 @@ namespace Database {
 
     TrackBookmark::pointer TrackBookmark::find(Session& session, TrackBookmarkId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<TrackBookmark>()
             .where("id = ?").bind(id)

src/libs/services/database/impl/TrackFeatures.cpp

@@ -43,14 +43,14 @@ namespace Database {
 
     std::size_t TrackFeatures::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM track_features");
     }
 
     TrackFeatures::pointer TrackFeatures::find(Session& session, TrackFeaturesId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<TrackFeatures>()
             .where("id = ?").bind(id)
@@ -59,7 +59,7 @@ namespace Database {
 
     TrackFeatures::pointer TrackFeatures::find(Session& session, TrackId trackId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<TrackFeatures>()
             .where("track_id = ?").bind(trackId)
@@ -68,7 +68,7 @@ namespace Database {
 
     RangeResults<TrackFeaturesId> TrackFeatures::find(Session& session, std::optional<Range> range)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<TrackFeaturesId>("SELECT id from track_features") };
 

src/libs/services/database/impl/TrackList.cpp

@@ -53,7 +53,7 @@ namespace Database
 
     std::size_t TrackList::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM tracklist");
     }
@@ -61,7 +61,7 @@ namespace Database
 
     TrackList::pointer TrackList::find(Session& session, std::string_view name, TrackListType type, UserId userId)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
         assert(userId.isValid());
 
         return session.getDboSession().find<TrackList>()
@@ -72,7 +72,7 @@ namespace Database
 
     RangeResults<TrackListId> TrackList::find(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<TrackListId>("SELECT DISTINCT t_l.id FROM tracklist t_l") };
 
@@ -122,7 +122,7 @@ namespace Database
 
     TrackList::pointer TrackList::find(Session& session, TrackListId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<TrackList>().where("id = ?").bind(id).resultValue();
     }
@@ -323,7 +323,7 @@ namespace Database
 
     TrackListEntry::pointer TrackListEntry::getById(Session& session, TrackListEntryId id)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<TrackListEntry>().where("id = ?").bind(id).resultValue();
     }

src/libs/services/database/impl/TransactionChecker.cpp

@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2023 Emeric Poupon
+ *
+ * This file is part of LMS.
+ *
+ * LMS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LMS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "services/database/TransactionChecker.hpp"
+
+#include <cassert>
+
+#include "services/database/Session.hpp"
+
+#if !defined(NDEBUG)
+#define LMS_CHECK_TRANSACTION_ACCESSES 1
+#else
+#define LMS_CHECK_TRANSACTION_ACCESSES 0
+#endif
+
+namespace Database
+{
+#if LMS_CHECK_TRANSACTION_ACCESSES
+    namespace
+    {
+        struct StackEntry
+        {
+            TransactionChecker::TransactionType type;
+            Wt::Dbo::Session* session{};
+        };
+
+        static thread_local std::vector<StackEntry> transactionStack;
+    }
+#endif
+
+    void TransactionChecker::pushWriteTransaction(Wt::Dbo::Session& session)
+    {
+        pushTransaction(TransactionType::Write, session);
+    }
+
+    void TransactionChecker::pushReadTransaction(Wt::Dbo::Session& session)
+    {
+        pushTransaction(TransactionType::Read, session);
+    }
+
+    void TransactionChecker::popWriteTransaction(Wt::Dbo::Session& session)
+    {
+        popTransaction(TransactionType::Write, session);
+    }
+
+    void TransactionChecker::popReadTransaction(Wt::Dbo::Session& session)
+    {
+        popTransaction(TransactionType::Read, session);
+    }
+
+    void TransactionChecker::pushTransaction(TransactionType type, Wt::Dbo::Session& session)
+    {
+#if LMS_CHECK_TRANSACTION_ACCESSES
+        assert(transactionStack.empty() || transactionStack.back().session == &session);
+        transactionStack.push_back(StackEntry{ type, &session });
+#endif // LMS_CHECK_TRANSACTION_ACCESSES
+    }
+
+    void TransactionChecker::popTransaction(TransactionType type, Wt::Dbo::Session& session)
+    {
+#if LMS_CHECK_TRANSACTION_ACCESSES
+
+        assert(!transactionStack.empty());
+        assert(transactionStack.back().type == type);
+        assert(transactionStack.back().session == &session);
+        transactionStack.pop_back();
+#endif // LMS_CHECK_TRANSACTION_ACCESSES
+
+    }
+
+    void TransactionChecker::checkWriteTransaction(Wt::Dbo::Session& session)
+    {
+        assert(!transactionStack.empty());
+        assert(transactionStack.back().type == TransactionType::Write);
+        assert(transactionStack.back().session == &session);
+    }
+
+    void TransactionChecker::checkWriteTransaction(Session& session)
+    {
+        checkWriteTransaction(session.getDboSession());
+    }
+
+    void TransactionChecker::checkReadTransaction(Wt::Dbo::Session& session)
+    {
+        assert(!transactionStack.empty());
+        assert(transactionStack.back().session == &session);
+    }
+
+    void TransactionChecker::checkReadTransaction(Session& session)
+    {
+        checkReadTransaction(session.getDboSession());
+    }
+}

src/libs/services/database/impl/User.cpp

@@ -42,14 +42,14 @@ namespace Database {
 
     std::size_t User::getCount(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().query<int>("SELECT COUNT(*) FROM user");
     }
 
     RangeResults<UserId> User::find(Session& session, const FindParameters& params)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         auto query{ session.getDboSession().query<UserId>("SELECT id FROM user") };
 
@@ -63,7 +63,7 @@ namespace Database {
 
     User::pointer User::findDemoUser(Session& session)
     {
-        session.checkSharedLocked();
+        session.checkReadTransaction();
 
         return session.getDboSession().find<User>().where("type = ?").bind(UserType::DEMO).resultValue();
     }

src/libs/services/database/include/services/database/Object.hpp

@@ -22,6 +22,7 @@
 #include <Wt/WSignal.h>
 #include <Wt/Dbo/ptr.h>
 #include "services/database/IdType.hpp"
+#include "services/database/TransactionChecker.hpp"
 
 namespace Database
 {
@@ -38,9 +39,11 @@ namespace Database
 			bool operator==(const ObjectPtr& other) const { return _obj == other._obj; }
 			bool operator!=(const ObjectPtr& other) const { return other._obj != _obj; }
 
-			auto modify() { return _obj.modify(); }
+			auto modify() { TransactionChecker::checkWriteTransaction(*_obj.session()); return _obj.modify(); }
 			void remove()
 			{
+				TransactionChecker::checkWriteTransaction(*_obj.session());
+
 				if (_obj->hasOnPreRemove())
 					_obj.modify()->onPreRemove();
 				_obj.remove();

src/libs/services/database/include/services/database/Session.hpp

@@ -24,27 +24,37 @@
 
 #include "utils/RecursiveSharedMutex.hpp"
 #include "services/database/Object.hpp"
-
+#include "services/database/TransactionChecker.hpp"
 
 namespace Database
 {
-    class UniqueTransaction
+    class WriteTransaction
     {
+    public:
+        ~WriteTransaction();
     private:
         friend class Session;
-        UniqueTransaction(RecursiveSharedMutex& mutex, Wt::Dbo::Session& session);
+        WriteTransaction(RecursiveSharedMutex& mutex, Wt::Dbo::Session& session);
+
+        WriteTransaction(const WriteTransaction&) = delete;
+        WriteTransaction& operator=(const WriteTransaction&) = delete;
 
         std::unique_lock<RecursiveSharedMutex> _lock;
         Wt::Dbo::Transaction _transaction;
     };
 
-    class SharedTransaction
+    class ReadTransaction
     {
+    public:
+        ~ReadTransaction();
     private:
         friend class Session;
-        SharedTransaction(RecursiveSharedMutex& mutex, Wt::Dbo::Session& session);
+        ReadTransaction(Wt::Dbo::Session& session);
+
+
+        ReadTransaction(const ReadTransaction&) = delete;
+        ReadTransaction& operator=(const ReadTransaction&) = delete;
 
-        std::shared_lock<RecursiveSharedMutex> _lock;
         Wt::Dbo::Transaction _transaction;
     };
 
@@ -54,11 +64,11 @@ namespace Database
     public:
         Session(Db& database);
 
-        [[nodiscard]] UniqueTransaction createUniqueTransaction();
+        [[nodiscard]] WriteTransaction createWriteTransaction();
-        [[nodiscard]] SharedTransaction createSharedTransaction();
+        [[nodiscard]] ReadTransaction createReadTransaction();
 
-        void checkUniqueLocked();
+        void checkWriteTransaction() { TransactionChecker::checkWriteTransaction(_session); }
-        void checkSharedLocked();
+        void checkReadTransaction() { TransactionChecker::checkReadTransaction(_session); }
 
         void analyze();
         void optimize();
@@ -71,7 +81,7 @@ namespace Database
         template <typename Object, typename... Args>
         typename Object::pointer create(Args&&... args)
         {
-            checkUniqueLocked();
+            TransactionChecker::checkWriteTransaction(_session);
 
             typename Object::pointer res{ Object::create(*this, std::forward<Args>(args)...) };
             getDboSession().flush();
@@ -90,5 +100,3 @@ namespace Database
         Wt::Dbo::Session	_session;
     };
 } // namespace Database
-
-

src/libs/services/database/include/services/database/TransactionChecker.hpp

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2023 Emeric Poupon
+ *
+ * This file is part of LMS.
+ *
+ * LMS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LMS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <vector>
+#include <Wt/Dbo/Session.h>
+
+namespace Database
+{
+    class Session;
+
+    class TransactionChecker
+    {
+    public:
+        enum class TransactionType
+        {
+            Read,
+            Write,
+        };
+
+        static void pushWriteTransaction(Wt::Dbo::Session& session);
+        static void pushReadTransaction(Wt::Dbo::Session& session);
+
+        static void popWriteTransaction(Wt::Dbo::Session& session);
+        static void popReadTransaction(Wt::Dbo::Session& session);
+
+        static void checkWriteTransaction(Wt::Dbo::Session& session);
+        static void checkWriteTransaction(Session& session);
+        static void checkReadTransaction(Wt::Dbo::Session& session);
+        static void checkReadTransaction(Session& session);
+
+    private:
+        static void pushTransaction(TransactionType type, Wt::Dbo::Session& session);
+        static void popTransaction(TransactionType type, Wt::Dbo::Session& session);
+    };
+}

src/libs/services/database/test/Artist.cpp

@@ -24,7 +24,7 @@ using namespace Database;
 TEST_F(DatabaseFixture, Artist)
 {
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_FALSE(Artist::exists(session, 35));
         EXPECT_FALSE(Artist::exists(session, 0));
         EXPECT_FALSE(Artist::exists(session, 1));
@@ -34,7 +34,7 @@ TEST_F(DatabaseFixture, Artist)
     ScopedArtist artist{ session, "MyArtist" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_TRUE(artist.get());
         EXPECT_FALSE(!artist.get());
@@ -45,7 +45,7 @@ TEST_F(DatabaseFixture, Artist)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Artist::findIds(session, Artist::FindParameters {}) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -58,7 +58,7 @@ TEST_F(DatabaseFixture, Artist)
 
     
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Artist::find(session, Artist::FindParameters {}) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -66,7 +66,7 @@ TEST_F(DatabaseFixture, Artist)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         bool visited{};
         Artist::find(session, Artist::FindParameters{}, [&](const Artist::pointer& a)
@@ -84,19 +84,19 @@ TEST_F(DatabaseFixture, Artist_singleTrack)
     ScopedArtist artist{ session, "MyArtist" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track.get().modify()->setName("MyTrackName");
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(Artist::findOrphanIds(session).results.empty());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ track->getArtists({TrackArtistLinkType::Artist}) };
         ASSERT_EQ(artists.size(), 1);
@@ -113,7 +113,7 @@ TEST_F(DatabaseFixture, Artist_singleTrack)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ track->getArtistIds({TrackArtistLinkType::Artist}) };
         ASSERT_EQ(artists.size(), 1);
@@ -125,23 +125,23 @@ TEST_F(DatabaseFixture, Artist_singleTrack)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto tracks{ Track::findIds(session, Track::FindParameters{}.setName("MyTrackName").setArtistName("MyArtist")) };
         ASSERT_EQ(tracks.results.size(), 1);
         EXPECT_EQ(tracks.results.front(), track.getId());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto tracks{ Track::findIds(session, Track::FindParameters{}.setName("MyTrackName").setArtistName("MyArtistFoo")) };
         EXPECT_EQ(tracks.results.size(), 0);
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto tracks{ Track::findIds(session, Track::FindParameters{}.setName("MyTrackNameFoo").setArtistName("MyArtist")) };
         EXPECT_EQ(tracks.results.size(), 0);
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto artists{ Artist::findIds(session, Artist::FindParameters{}.setTrack(track->getId())) };
         ASSERT_EQ(artists.results.size(), 1);
         EXPECT_EQ(artists.results.front(), artist.getId());
@@ -153,7 +153,7 @@ TEST_F(DatabaseFixture, Artist_singleTracktMultiRoles)
     ScopedTrack track{ session, "MyTrack" };
     ScopedArtist artist{ session, "MyArtist" };
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::ReleaseArtist);
@@ -161,12 +161,12 @@ TEST_F(DatabaseFixture, Artist_singleTracktMultiRoles)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(Artist::findOrphanIds(session, Range{}).results.empty());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(Artist::findIds(session, Artist::FindParameters{}).results.size(), 1);
         EXPECT_EQ(Artist::findIds(session, Artist::FindParameters{}.setLinkType(TrackArtistLinkType::Artist)).results.size(), 1);
         EXPECT_EQ(Artist::findIds(session, Artist::FindParameters{}.setLinkType(TrackArtistLinkType::ReleaseArtist)).results.size(), 1);
@@ -175,7 +175,7 @@ TEST_F(DatabaseFixture, Artist_singleTracktMultiRoles)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ track->getArtists({TrackArtistLinkType::Artist}) };
         ASSERT_EQ(artists.size(), 1);
@@ -202,7 +202,7 @@ TEST_F(DatabaseFixture, Artist_singleTracktMultiRoles)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EnumSet<TrackArtistLinkType> types{ TrackArtistLink::findUsedTypes(session, artist.getId()) };
         EXPECT_TRUE(types.contains(TrackArtistLinkType::ReleaseArtist));
         EXPECT_TRUE(types.contains(TrackArtistLinkType::Artist));
@@ -219,19 +219,19 @@ TEST_F(DatabaseFixture, Artist_singleTrackMultiArtists)
     ASSERT_NE(artist1.getId(), artist2.getId());
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         TrackArtistLink::create(session, track.get(), artist1.get(), TrackArtistLinkType::Artist);
         TrackArtistLink::create(session, track.get(), artist2.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(Artist::findOrphanIds(session).results.empty());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ track->getArtists({TrackArtistLinkType::Artist}) };
         ASSERT_EQ(artists.size(), 2);
@@ -246,7 +246,7 @@ TEST_F(DatabaseFixture, Artist_singleTrackMultiArtists)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Track::findIds(session, Track::FindParameters {}.setArtist(artist1->getId())) };
         ASSERT_EQ(tracks.results.size(), 1);
@@ -276,13 +276,13 @@ TEST_F(DatabaseFixture, Artist_findByName)
     ScopedTrack track{ session, "MyTrack" }; // filters does not work on orphans
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         artist.get().modify()->setSortName("ZZZ");
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_TRUE(Artist::findIds(session, Artist::FindParameters{}.setKeywords({ "N" })).results.empty());
 
@@ -310,7 +310,7 @@ TEST_F(DatabaseFixture, Artist_findByNameEscaped)
     ScopedArtist artist6{ session, R"(%AMyArtist)" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         {
             const auto artists{ Artist::find(session, R"(MyArtist%)") };
             ASSERT_TRUE(artists.size() == 1);
@@ -332,7 +332,7 @@ TEST_F(DatabaseFixture, Artist_findByNameEscaped)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         {
             const auto artists{ Artist::findIds(session, Artist::FindParameters {}.setKeywords({"MyArtist"})) };
             EXPECT_EQ(artists.results.size(), 6);
@@ -366,14 +366,14 @@ TEST_F(DatabaseFixture, Artist_sortMethod)
     ScopedArtist artistB{ session, "artistB" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         artistA.get().modify()->setSortName("sortNameB");
         artistB.get().modify()->setSortName("sortNameA");
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto allArtistsByName{ Artist::findIds(session, Artist::FindParameters {}.setSortMethod(ArtistSortMethod::ByName)) };
         auto allArtistsBySortName{ Artist::findIds(session, Artist::FindParameters {}.setSortMethod(ArtistSortMethod::BySortName)) };
@@ -396,14 +396,14 @@ TEST_F(DatabaseFixture, Artist_nonReleaseTracks)
     ScopedRelease release{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Track::findIds(session, Track::FindParameters {}.setNonRelease(true).setArtist(artist->getId())) };
         EXPECT_EQ(tracks.results.size(), 0);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         TrackArtistLink::create(session, track1.get(), artist.get(), TrackArtistLinkType::Artist);
         TrackArtistLink::create(session, track2.get(), artist.get(), TrackArtistLinkType::Artist);
@@ -412,7 +412,7 @@ TEST_F(DatabaseFixture, Artist_nonReleaseTracks)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto tracks{ Track::findIds(session, Track::FindParameters {}.setArtist(artist.getId()).setNonRelease(true)) };
         ASSERT_EQ(tracks.results.size(), 1);
@@ -427,29 +427,29 @@ TEST_F(DatabaseFixture, Artist_findByRelease)
     ScopedRelease release{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         const auto artists{ Artist::findIds(session, Artist::FindParameters {}.setRelease(release.getId())) };
         EXPECT_EQ(artists.results.size(), 0);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         const auto artists{ Artist::findIds(session, Artist::FindParameters {}.setRelease(release.getId())) };
         EXPECT_EQ(artists.results.size(), 0);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setRelease(release.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         const auto artists{ Artist::findIds(session, Artist::FindParameters {}.setRelease(release.getId())) };
         ASSERT_EQ(artists.results.size(), 1);
         EXPECT_EQ(artists.results.front(), artist.getId());

src/libs/services/database/test/Cluster.cpp

@@ -27,7 +27,7 @@ using namespace Database;
 TEST_F(DatabaseFixture, Cluster)
 {
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         EXPECT_EQ(Cluster::getCount(session), 0);
         EXPECT_EQ(ClusterType::getCount(session), 0);
     }
@@ -35,7 +35,7 @@ TEST_F(DatabaseFixture, Cluster)
     ScopedClusterType clusterType{ session, "MyType" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         EXPECT_EQ(ClusterType::getCount(session), 1);
     }
 
@@ -43,7 +43,7 @@ TEST_F(DatabaseFixture, Cluster)
         ScopedCluster cluster{ session, clusterType.lockAndGet(), "MyCluster" };
 
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             EXPECT_EQ(Cluster::getCount(session), 1);
             EXPECT_EQ(cluster->getType()->getId(), clusterType.getId());
@@ -74,7 +74,7 @@ TEST_F(DatabaseFixture, Cluster)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto clusterTypes{ ClusterType::findOrphans(session) };
         ASSERT_EQ(clusterTypes.results.size(), 1);
@@ -90,7 +90,7 @@ TEST_F(DatabaseFixture, Cluster_singleTrack)
     ScopedClusterType clusterType{ session, "MyClusterType" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(Cluster::findOrphans(session).results.empty());
         auto clusterTypes{ ClusterType::findOrphans(session) };
         ASSERT_EQ(clusterTypes.results.size(), 1);
@@ -101,7 +101,7 @@ TEST_F(DatabaseFixture, Cluster_singleTrack)
     ScopedCluster cluster2{ session, clusterType.lockAndGet(), "MyCluster2" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto clusters{ Cluster::findOrphans(session) };
         EXPECT_EQ(clusters.results.size(), 2);
         EXPECT_TRUE(track->getClusters().empty());
@@ -111,13 +111,13 @@ TEST_F(DatabaseFixture, Cluster_singleTrack)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         cluster1.get().modify()->addTrack(track.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto clusters{ Cluster::findIds(session, Cluster::FindParameters {}.setTrack(track.getId())) };
         ASSERT_EQ(clusters.results.size(), 1);
         EXPECT_EQ(clusters.results.front(), cluster1.getId());
@@ -126,7 +126,7 @@ TEST_F(DatabaseFixture, Cluster_singleTrack)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto clusters{ Cluster::findOrphans(session) };
         ASSERT_EQ(clusters.results.size(), 1);
         EXPECT_EQ(clusters.results.front(), cluster2.getId());
@@ -135,7 +135,7 @@ TEST_F(DatabaseFixture, Cluster_singleTrack)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Track::findIds(session, Track::FindParameters {}.setClusters({cluster1.getId()})) };
         ASSERT_EQ(tracks.results.size(), 1);
@@ -146,7 +146,7 @@ TEST_F(DatabaseFixture, Cluster_singleTrack)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto clusters{ track->getClusters() };
         ASSERT_EQ(clusters.size(), 1);
@@ -169,20 +169,20 @@ TEST_F(DatabaseFixture, Cluster_singleTrackWithSeveralClusters)
     const std::vector<ClusterId> clusterIds{ cluster1.getId(), cluster2.getId() };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto tracks{ Track::findIds(session, Track::FindParameters{}.setClusters(clusterIds)) };
         EXPECT_TRUE(tracks.results.empty());
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         cluster1.get().modify()->addTrack(track.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto tracks{ Track::findIds(session, Track::FindParameters{}.setClusters(clusterIds)) };
         EXPECT_TRUE(tracks.results.empty());
@@ -191,13 +191,13 @@ TEST_F(DatabaseFixture, Cluster_singleTrackWithSeveralClusters)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         cluster2.get().modify()->addTrack(track.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto tracks{ Track::findIds(session, Track::FindParameters{}.setClusters(clusterIds)) };
         ASSERT_FALSE(tracks.results.empty());
@@ -218,13 +218,13 @@ TEST_F(DatabaseFixture, Cluster_multiTracks)
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
             cluster.get().modify()->addTrack(tracks.back().get());
         }
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(Cluster::findOrphans(session).results.empty());
 
         EXPECT_EQ(Cluster::computeTrackCount(session, cluster.getId()), tracks.size());
@@ -243,7 +243,7 @@ TEST_F(DatabaseFixture, Cluster_singleTrackSingleReleaseSingleCluster)
     ScopedRelease release{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(Cluster::findOrphans(session).results.empty());
     }
 
@@ -252,7 +252,7 @@ TEST_F(DatabaseFixture, Cluster_singleTrackSingleReleaseSingleCluster)
     ScopedCluster unusedCluster{ session, clusterType.lockAndGet(), "MyClusterUnused" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         ASSERT_EQ(Cluster::findOrphans(session).results.size(), 2);
         EXPECT_TRUE(Release::find(session, Release::FindParameters{}.setClusters({ unusedCluster.getId() })).results.empty());
         EXPECT_EQ(Release::find(session, Release::FindParameters{}).results.size(), 1);
@@ -261,14 +261,14 @@ TEST_F(DatabaseFixture, Cluster_singleTrackSingleReleaseSingleCluster)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track.get().modify()->setRelease(release.get());
         cluster.get().modify()->addTrack(track.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             auto clusters{ Cluster::findOrphans(session) };
@@ -280,7 +280,7 @@ TEST_F(DatabaseFixture, Cluster_singleTrackSingleReleaseSingleCluster)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto clusters{ Cluster::findIds(session, Cluster::FindParameters{}.setRelease(release.getId())) };
         ASSERT_EQ(clusters.results.size(), 1);
@@ -288,7 +288,7 @@ TEST_F(DatabaseFixture, Cluster_singleTrackSingleReleaseSingleCluster)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setClusters({cluster.getId()})) };
         ASSERT_EQ(releases.results.size(), 1);
@@ -296,14 +296,14 @@ TEST_F(DatabaseFixture, Cluster_singleTrackSingleReleaseSingleCluster)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setClusters({unusedCluster.getId()})) };
         EXPECT_EQ(releases.results.size(), 0);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_EQ(Cluster::computeReleaseCount(session, cluster.getId()), 1);
         EXPECT_EQ(Cluster::computeTrackCount(session, cluster.getId()), 1);
@@ -321,14 +321,14 @@ TEST_F(DatabaseFixture, SingleTrackSingleArtistMultiClusters)
     ScopedCluster cluster2{ session, clusterType.lockAndGet(), "Cluster2" };
     ScopedCluster cluster3{ session, clusterType.lockAndGet(), "Cluster3" };
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto trackArtistLink{ TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist) };
         cluster1.get().modify()->addTrack(track.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(ClusterType::findOrphans(session).results.empty());
         EXPECT_EQ(Cluster::findOrphans(session).results.size(), 2);
         EXPECT_TRUE(Release::findOrphanIds(session).results.empty());
@@ -336,13 +336,13 @@ TEST_F(DatabaseFixture, SingleTrackSingleArtistMultiClusters)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(track->getClusters().size(), 1);
         EXPECT_EQ(track->getClusterIds().size(), 1);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto artists{ Artist::findIds(session, Artist::FindParameters {}.setClusters({cluster1.getId()})) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -355,7 +355,7 @@ TEST_F(DatabaseFixture, SingleTrackSingleArtistMultiClusters)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Artist::findIds(session, Artist::FindParameters {}.setClusters({cluster1.getId()})) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -381,7 +381,7 @@ TEST_F(DatabaseFixture, SingleTrackSingleArtistMultiRolesMultiClusters)
     ScopedCluster cluster{ session, clusterType.lockAndGet(), "MyCluster" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::ReleaseArtist);
@@ -389,14 +389,14 @@ TEST_F(DatabaseFixture, SingleTrackSingleArtistMultiRolesMultiClusters)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(Cluster::findOrphans(session).results.empty());
         EXPECT_TRUE(Release::findOrphanIds(session).results.empty());
         EXPECT_TRUE(Artist::findOrphanIds(session).results.empty());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Artist::findIds(session, Artist::FindParameters {}.setClusters({cluster.getId()})) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -421,7 +421,7 @@ TEST_F(DatabaseFixture, MultiTracksSingleArtistMultiClusters)
     {
         tracks.emplace_back(session, "MyTrackFile" + std::to_string(i));
 
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         TrackArtistLink::create(session, tracks.back().get(), artist.get(), TrackArtistLinkType::Artist);
 
         for (auto& cluster : clusters)
@@ -429,13 +429,13 @@ TEST_F(DatabaseFixture, MultiTracksSingleArtistMultiClusters)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(Cluster::findOrphans(session).results.empty());
         EXPECT_TRUE(Artist::findOrphanIds(session).results.empty());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         std::vector<ClusterId> clusterIds;
         std::transform(std::cbegin(clusters), std::cend(clusters), std::back_inserter(clusterIds), [](const ScopedCluster& cluster) { return cluster.getId(); });
@@ -458,13 +458,13 @@ TEST_F(DatabaseFixture, MultipleTracksSingleClusterSimilarity)
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
             cluster.get().modify()->addTrack(tracks.back().get());
         }
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto similarTracks{ Track::findSimilarTrackIds(session, {tracks.front().getId()}) };
         EXPECT_EQ(similarTracks.results.size(), tracks.size() - 1);
@@ -487,7 +487,7 @@ TEST_F(DatabaseFixture, MultipleTracksMultipleClustersSimilarity)
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
             cluster1.get().modify()->addTrack(tracks.back().get());
         }
     }
@@ -497,14 +497,14 @@ TEST_F(DatabaseFixture, MultipleTracksMultipleClustersSimilarity)
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
             cluster1.get().modify()->addTrack(tracks.back().get());
             cluster2.get().modify()->addTrack(tracks.back().get());
         }
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             auto similarTracks{ Track::findSimilarTrackIds(session, {tracks.back().getId()}, Range {0, 4}) };
@@ -531,7 +531,7 @@ TEST_F(DatabaseFixture, SingleTrackSingleReleaseSingleArtistSingleCluster)
     ScopedCluster cluster{ session, clusterType.lockAndGet(), "MyCluster" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
         track.get().modify()->setRelease(release.get());
@@ -539,7 +539,7 @@ TEST_F(DatabaseFixture, SingleTrackSingleReleaseSingleArtistSingleCluster)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_TRUE(Cluster::findOrphans(session).results.empty());
         EXPECT_TRUE(ClusterType::findOrphans(session).results.empty());
@@ -548,7 +548,7 @@ TEST_F(DatabaseFixture, SingleTrackSingleReleaseSingleArtistSingleCluster)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Artist::findIds(session, Artist::FindParameters {}.setClusters({cluster.getId()})) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -574,7 +574,7 @@ TEST_F(DatabaseFixture, SingleTrackSingleReleaseSingleArtistMultiClusters)
     ScopedCluster cluster2{ session, clusterType.lockAndGet(), "MyCluster2" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto trackArtistLink{ TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist) };
         track.get().modify()->setRelease(release.get());
@@ -583,7 +583,7 @@ TEST_F(DatabaseFixture, SingleTrackSingleReleaseSingleArtistMultiClusters)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Release::findIds(session, Release::FindParameters {}.setArtist(artist.getId())) };
         ASSERT_EQ(releases.results.size(), 1);
@@ -607,7 +607,7 @@ TEST_F(DatabaseFixture, SingleTrackListMultipleTrackSingleCluster)
     {
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         if (i < 5)
             session.create<TrackListEntry>(tracks.back().get(), trackList.get());
@@ -617,7 +617,7 @@ TEST_F(DatabaseFixture, SingleTrackListMultipleTrackSingleCluster)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto similarTracks{ trackList->getSimilarTracks() };
         EXPECT_EQ(similarTracks.size(), 5);
@@ -640,7 +640,7 @@ TEST_F(DatabaseFixture, SingleTrackListMultipleTrackMultiClusters)
     {
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         if (i < 5)
             session.create<TrackListEntry>(tracks.back().get(), trackList.get());
@@ -657,7 +657,7 @@ TEST_F(DatabaseFixture, SingleTrackListMultipleTrackMultiClusters)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             const auto similarTracks{ trackList->getSimilarTracks(0, 5) };
@@ -689,7 +689,7 @@ TEST_F(DatabaseFixture, MultipleTracksMultipleArtistsMultiClusters)
     ScopedCluster cluster2{ session, clusterType.lockAndGet(), "MyCluster2" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(artist1->findSimilarArtistIds().results.empty());
         EXPECT_TRUE(artist2->findSimilarArtistIds().results.empty());
         EXPECT_TRUE(artist3->findSimilarArtistIds().results.empty());
@@ -700,7 +700,7 @@ TEST_F(DatabaseFixture, MultipleTracksMultipleArtistsMultiClusters)
     {
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         if (i < 5)
             TrackArtistLink::create(session, tracks.back().get(), artist1.get(), TrackArtistLinkType::Artist);
@@ -715,13 +715,13 @@ TEST_F(DatabaseFixture, MultipleTracksMultipleArtistsMultiClusters)
 
     tracks.emplace_back(session, "MyTrack" + std::to_string(tracks.size()));
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         TrackArtistLink::create(session, tracks.back().get(), artist3.get(), TrackArtistLinkType::Artist);
         cluster2.get().modify()->addTrack(tracks.back().get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             auto artists{ artist1->findSimilarArtistIds() };
@@ -770,7 +770,7 @@ TEST_F(DatabaseFixture, MultipleTracksMultipleReleasesMultiClusters)
     ScopedCluster cluster2{ session, clusterType.lockAndGet(), "MyCluster2" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(release1->getSimilarReleases().empty());
         EXPECT_TRUE(release2->getSimilarReleases().empty());
         EXPECT_TRUE(release3->getSimilarReleases().empty());
@@ -781,7 +781,7 @@ TEST_F(DatabaseFixture, MultipleTracksMultipleReleasesMultiClusters)
     {
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         if (i < 5)
             tracks.back().get().modify()->setRelease(release1.get());
@@ -796,13 +796,13 @@ TEST_F(DatabaseFixture, MultipleTracksMultipleReleasesMultiClusters)
 
     tracks.emplace_back(session, "MyTrack" + std::to_string(tracks.size()));
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         tracks.back().get().modify()->setRelease(release3.get());
         cluster2.get().modify()->addTrack(tracks.back().get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             auto releases{ release1->getSimilarReleases() };

src/libs/services/database/test/Common.cpp

@@ -62,7 +62,7 @@ void DatabaseFixture::SetUpTestCase()
 
         // remove default created entries
         {
-            auto transaction{ s.createUniqueTransaction() };
+            auto transaction{ s.createWriteTransaction() };
 
             for (const Database::ClusterTypeId clusterTypeId : Database::ClusterType::find(s).results)
             {
@@ -82,7 +82,7 @@ void DatabaseFixture::testDatabaseEmpty()
 {
     using namespace Database;
 
-    auto uniqueTransaction{ session.createUniqueTransaction() };
+    auto transaction{ session.createWriteTransaction() };
 
     EXPECT_EQ(Artist::getCount(session), 0);
     EXPECT_EQ(Cluster::getCount(session), 0);

src/libs/services/database/test/Common.hpp

@@ -49,7 +49,7 @@ class ScopedEntity
 		ScopedEntity(Database::Session& session, Args&& ...args)
 			: _session {session}
 		{
-			auto transaction {_session.createUniqueTransaction()};
+			auto transaction {_session.createWriteTransaction()};
 
 			auto entity {_session.create<T>(std::forward<Args>(args)...)};
 			EXPECT_TRUE(entity);
@@ -58,7 +58,7 @@ class ScopedEntity
 
 		~ScopedEntity()
 		{
-			auto transaction {_session.createUniqueTransaction()};
+			auto transaction {_session.createWriteTransaction()};
 
 			auto entity {T::find(_session, _id)};
 			// could not be here due to "on delete cascade" constraints...
@@ -73,13 +73,13 @@ class ScopedEntity
 
 		typename T::pointer lockAndGet()
 		{
-			auto transaction {_session.createSharedTransaction()};
+			auto transaction {_session.createReadTransaction()};
 			return get();
 		}
 
 		typename T::pointer get()
 		{
-			_session.checkSharedLocked();
+			_session.checkReadTransaction();
 
 			auto entity {T::find(_session, _id)};
 			EXPECT_TRUE(entity);

src/libs/services/database/test/DatabaseTest.cpp

@@ -34,20 +34,20 @@ TEST_F(DatabaseFixture, MultiTracksSingleArtistSingleRelease)
     {
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         TrackArtistLink::create(session, tracks.back().get(), artist.get(), TrackArtistLinkType::Artist);
         tracks.back().get().modify()->setRelease(release.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(Release::findOrphanIds(session).results.empty());
         EXPECT_TRUE(Artist::findOrphanIds(session).results.empty());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Release::findIds(session, Release::FindParameters {}.setArtist(artist.getId())) };
         ASSERT_EQ(releases.results.size(), 1);
@@ -65,14 +65,14 @@ TEST_F(DatabaseFixture, SingleTrackSingleReleaseSingleArtist)
     ScopedArtist artist{ session, "MyArtist" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto trackArtistLink{ TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist) };
         track.get().modify()->setRelease(release.get());
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto releases{ Release::findIds(session, Release::FindParameters {}.setArtist(artist.getId())) };
         ASSERT_EQ(releases.results.size(), 1);
@@ -87,7 +87,7 @@ TEST_F(DatabaseFixture, SingleTrackSingleReleaseSingleArtist)
 TEST_F(DatabaseFixture, SingleUser)
 {
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_TRUE(User::find(session, User::FindParameters{}).results.empty());
         EXPECT_EQ(User::getCount(session), 0);
     }
@@ -95,7 +95,7 @@ TEST_F(DatabaseFixture, SingleUser)
     ScopedUser user{ session, "MyUser" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_EQ(User::find(session, User::FindParameters{}).results.size(), 1);
         EXPECT_EQ(User::getCount(session), 1);

src/libs/services/database/test/Listen.cpp

@@ -30,7 +30,7 @@ TEST_F(DatabaseFixture, Listen_getAll)
     ScopedUser user{ session, "MyUser" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_EQ(Listen::getCount(session), 0);
     }
@@ -38,20 +38,20 @@ TEST_F(DatabaseFixture, Listen_getAll)
     ScopedListen listen{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, Wt::WDateTime {Wt::WDate{2000, 1, 2}, Wt::WTime{12, 0, 1}} };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_EQ(Listen::getCount(session), 1);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         ScopedListen listen2{ session, user.get(), track.get(), ScrobblingBackend::Internal, Wt::WDateTime {Wt::WDate{2000, 1, 2}, Wt::WTime{13, 0, 1}} };
 
         EXPECT_EQ(Listen::getCount(session), 2);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_EQ(Listen::getCount(session), 1);
     }
@@ -64,14 +64,14 @@ TEST_F(DatabaseFixture, Listen_get)
     ScopedListen listen{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, Wt::WDateTime {Wt::WDate{2000, 1, 2}, Wt::WTime{12, 0, 1}} };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto listens{ Listen::find(session, Listen::FindParameters{}.setUser(user->getId()).setScrobblingBackend(ScrobblingBackend::ListenBrainz)) };
         EXPECT_EQ(listens.results.size(), 0);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             auto listens{ Listen::find(session, Listen::FindParameters{}.setUser(user->getId()).setScrobblingBackend(ScrobblingBackend::Internal)) };
@@ -100,7 +100,7 @@ TEST_F(DatabaseFixture, Listen_get_multi)
     ScopedListen listen2{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, Wt::WDateTime {Wt::WDate{2000, 1, 2}, Wt::WTime{12, 0, 2}} };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto listens{ Listen::find(session, Listen::FindParameters{}.setUser(user->getId()).setScrobblingBackend(ScrobblingBackend::Internal)) };
         ASSERT_EQ(listens.results.size(), 3);
@@ -122,7 +122,7 @@ TEST_F(DatabaseFixture, Listen_get_byDateTime)
     ScopedListen listen2{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime2 };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             Listen::pointer listen{ Listen::find(session, user.getId(), track.getId(), ScrobblingBackend::Internal, dateTime1) };
@@ -151,7 +151,7 @@ TEST_F(DatabaseFixture, Listen_getTopArtists)
     ScopedListen listen1{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime1 };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         EXPECT_EQ(artists.results.size(), 0);
@@ -163,26 +163,26 @@ TEST_F(DatabaseFixture, Listen_getTopArtists)
     ScopedListen listen2{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime1.addSecs(1) };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         TrackArtistLink::create(session, track2.get(), artist1.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 1);
         EXPECT_EQ(artists.results[0], artist1->getId());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::ListenBrainz, {}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 0);
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {}, TrackArtistLinkType::Producer) };
         EXPECT_EQ(artists.results.size(), 0);
@@ -192,7 +192,7 @@ TEST_F(DatabaseFixture, Listen_getTopArtists)
         ScopedCluster cluster{ session, clusterType.lockAndGet(), "MyCluster" };
 
         {
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {cluster->getId()}, std::nullopt) };
             EXPECT_EQ(artists.results.size(), 0);
@@ -210,13 +210,13 @@ TEST_F(DatabaseFixture, Listen_getTopArtists_multi)
     const Wt::WDateTime dateTime{ Wt::WDate{2000, 1, 2}, Wt::WTime{12,0, 1} };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         TrackArtistLink::create(session, track1.get(), artist1.get(), TrackArtistLinkType::Artist);
         TrackArtistLink::create(session, track2.get(), artist2.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         EXPECT_EQ(artists.results.size(), 0);
@@ -224,7 +224,7 @@ TEST_F(DatabaseFixture, Listen_getTopArtists_multi)
 
     ScopedListen listen1{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(1) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -233,7 +233,7 @@ TEST_F(DatabaseFixture, Listen_getTopArtists_multi)
     ScopedListen listen2{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(2) };
     ScopedListen listen3{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(3) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 2);
@@ -241,7 +241,7 @@ TEST_F(DatabaseFixture, Listen_getTopArtists_multi)
         EXPECT_EQ(artists.results[1], artist1->getId());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt, Range {0, 1}) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -261,22 +261,22 @@ TEST_F(DatabaseFixture, Listen_getTopArtists_cluster)
     ScopedCluster cluster{ session, clusterType.lockAndGet(), "MyCluster" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 0);
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         cluster.get().modify()->addTrack(track.get());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getTopArtists(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -291,12 +291,12 @@ TEST_F(DatabaseFixture, Listen_getTopReleases)
     const Wt::WDateTime dateTime{ Wt::WDate{2000, 1, 2}, Wt::WTime{12,0, 1} };
     ScopedRelease release{ session, "MyRelease" };
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setRelease(release.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getTopReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -306,7 +306,7 @@ TEST_F(DatabaseFixture, Listen_getTopReleases)
     ScopedListen listen{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getTopReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -314,7 +314,7 @@ TEST_F(DatabaseFixture, Listen_getTopReleases)
         EXPECT_EQ(releases.results[0], release.getId());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getTopReleases(session, user->getId(), ScrobblingBackend::ListenBrainz, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -333,13 +333,13 @@ TEST_F(DatabaseFixture, Listen_getTopReleases_multi)
     ScopedRelease release2{ session, "MyRelease2" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track1.get().modify()->setRelease(release1.get());
         track2.get().modify()->setRelease(release2.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getTopReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -349,7 +349,7 @@ TEST_F(DatabaseFixture, Listen_getTopReleases_multi)
     ScopedListen listen2{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime };
     ScopedListen listen3{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getTopReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -360,7 +360,7 @@ TEST_F(DatabaseFixture, Listen_getTopReleases_multi)
     ScopedListen listen4{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime };
     ScopedListen listen5{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getTopReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -381,23 +381,23 @@ TEST_F(DatabaseFixture, Listen_getTopReleases_cluster)
     ScopedRelease release{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setRelease(release.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getTopReleases(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}) };
         EXPECT_EQ(releases.results.size(), 0);
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         cluster.get().modify()->addTrack(track.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getTopReleases(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}) };
         EXPECT_EQ(releases.results.size(), 1);
@@ -412,7 +412,7 @@ TEST_F(DatabaseFixture, Listen_getTopTracks)
     const Wt::WDateTime dateTime{ Wt::WDate{2000, 1, 2}, Wt::WTime{12,0, 1} };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getTopTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -422,7 +422,7 @@ TEST_F(DatabaseFixture, Listen_getTopTracks)
     ScopedListen listen{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getTopTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -430,7 +430,7 @@ TEST_F(DatabaseFixture, Listen_getTopTracks)
         EXPECT_EQ(tracks.results[0], track.getId());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getTopTracks(session, user->getId(), ScrobblingBackend::ListenBrainz, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -447,7 +447,7 @@ TEST_F(DatabaseFixture, Listen_getTopTrack_multi)
     ScopedListen listen1{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getTopTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -457,7 +457,7 @@ TEST_F(DatabaseFixture, Listen_getTopTrack_multi)
     ScopedListen listen2{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime };
     ScopedListen listen3{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getTopTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -468,7 +468,7 @@ TEST_F(DatabaseFixture, Listen_getTopTrack_multi)
     ScopedListen listen4{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime };
     ScopedListen listen5{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getTopTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -488,18 +488,18 @@ TEST_F(DatabaseFixture, Listen_getTopTracks_cluster)
     ScopedCluster cluster{ session, clusterType.lockAndGet(), "MyCluster" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getTopTracks(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}) };
         EXPECT_EQ(tracks.results.size(), 0);
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         cluster.get().modify()->addTrack(track.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getTopTracks(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}) };
         EXPECT_EQ(tracks.results.size(), 1);
@@ -514,12 +514,12 @@ TEST_F(DatabaseFixture, Listen_getRecentArtists)
     ScopedArtist artist{ session, "MyArtist" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         EXPECT_EQ(artists.results.size(), 0);
@@ -530,20 +530,20 @@ TEST_F(DatabaseFixture, Listen_getRecentArtists)
     ScopedListen listen1{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 1);
         EXPECT_EQ(artists.results[0], artist->getId());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::ListenBrainz, {}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 0);
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {}, TrackArtistLinkType::Producer) };
         EXPECT_EQ(artists.results.size(), 0);
@@ -553,7 +553,7 @@ TEST_F(DatabaseFixture, Listen_getRecentArtists)
         ScopedCluster cluster{ session, clusterType.lockAndGet(), "MyCluster" };
 
         {
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {cluster->getId()}, std::nullopt) };
             EXPECT_EQ(artists.results.size(), 0);
@@ -571,13 +571,13 @@ TEST_F(DatabaseFixture, Listen_getRecentArtists_multi)
     const Wt::WDateTime dateTime{ Wt::WDate{2000, 1, 2}, Wt::WTime{12,0, 1} };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         TrackArtistLink::create(session, track1.get(), artist1.get(), TrackArtistLinkType::Artist);
         TrackArtistLink::create(session, track2.get(), artist2.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         EXPECT_EQ(artists.results.size(), 0);
@@ -585,7 +585,7 @@ TEST_F(DatabaseFixture, Listen_getRecentArtists_multi)
 
     ScopedListen listen1{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(1) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -593,7 +593,7 @@ TEST_F(DatabaseFixture, Listen_getRecentArtists_multi)
     }
     ScopedListen listen2{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(2) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 2);
@@ -602,7 +602,7 @@ TEST_F(DatabaseFixture, Listen_getRecentArtists_multi)
     }
     ScopedListen listen3{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(-1) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {}, std::nullopt, Range {0, 1}) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -622,22 +622,22 @@ TEST_F(DatabaseFixture, Listen_getRecentArtists_cluster)
     ScopedCluster cluster{ session, clusterType.lockAndGet(), "MyCluster" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 0);
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         cluster.get().modify()->addTrack(track.get());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Listen::getRecentArtists(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}, std::nullopt) };
         ASSERT_EQ(artists.results.size(), 1);
@@ -652,12 +652,12 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases)
     ScopedRelease release{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setRelease(release.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -668,7 +668,7 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases)
     ScopedListen listen1{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -676,7 +676,7 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases)
         EXPECT_EQ(releases.results[0], release.getId());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::ListenBrainz, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -692,12 +692,12 @@ TEST_F(DatabaseFixture, Listen_getMostRecentRelease)
     ScopedRelease release{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setRelease(release.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto listen{ Listen::getMostRecentListen(session, user->getId(), ScrobblingBackend::Internal, release.getId()) };
         EXPECT_FALSE(listen);
@@ -707,7 +707,7 @@ TEST_F(DatabaseFixture, Listen_getMostRecentRelease)
     ScopedListen listen1{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime1 };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto listen{ Listen::getMostRecentListen(session, user->getId(), ScrobblingBackend::Internal, release.getId()) };
         EXPECT_TRUE(listen);
@@ -718,7 +718,7 @@ TEST_F(DatabaseFixture, Listen_getMostRecentRelease)
     ScopedListen listen2{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime2 };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto listen{ Listen::getMostRecentListen(session, user->getId(), ScrobblingBackend::Internal, release.getId()) };
         EXPECT_TRUE(listen);
@@ -729,7 +729,7 @@ TEST_F(DatabaseFixture, Listen_getMostRecentRelease)
     ScopedListen listen3{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime3 };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto listen{ Listen::getMostRecentListen(session, user->getId(), ScrobblingBackend::Internal, release.getId()) };
         EXPECT_TRUE(listen);
@@ -746,7 +746,7 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases_multi)
     ScopedRelease release2{ session, "MyRelease2" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track1.get().modify()->setRelease(release1.get());
         track2.get().modify()->setRelease(release2.get());
     }
@@ -755,7 +755,7 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases_multi)
     ScopedListen listen1{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -765,7 +765,7 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases_multi)
 
     ScopedListen listen2{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(1) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -776,7 +776,7 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases_multi)
 
     ScopedListen listen3{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(2) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -787,7 +787,7 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases_multi)
 
     ScopedListen listen4{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(-1) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(releases.moreResults, false);
@@ -806,11 +806,11 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases_cluster)
     ScopedRelease release{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setRelease(release.get());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}) };
         EXPECT_EQ(releases.results.size(), 0);
@@ -820,18 +820,18 @@ TEST_F(DatabaseFixture, Listen_getRecentReleases_cluster)
     ScopedListen listen{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}) };
         EXPECT_EQ(releases.results.size(), 0);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         cluster.get().modify()->addTrack(track.get());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Listen::getRecentReleases(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}) };
         EXPECT_EQ(releases.results.size(), 1);
@@ -845,7 +845,7 @@ TEST_F(DatabaseFixture, Listen_getRecentTracks)
     ScopedUser user{ session, "MyUser" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getRecentTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -856,7 +856,7 @@ TEST_F(DatabaseFixture, Listen_getRecentTracks)
     ScopedListen listen1{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getRecentTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -865,7 +865,7 @@ TEST_F(DatabaseFixture, Listen_getRecentTracks)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getRecentTracks(session, user->getId(), ScrobblingBackend::ListenBrainz, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -879,7 +879,7 @@ TEST_F(DatabaseFixture, Listen_getCount_track)
     ScopedUser user{ session, "MyUser" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const std::size_t count{ Listen::getCount(session, user->getId(), ScrobblingBackend::Internal, track.getId()) };
         EXPECT_EQ(count, 0);
@@ -889,7 +889,7 @@ TEST_F(DatabaseFixture, Listen_getCount_track)
     ScopedListen listen1{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime1 };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const std::size_t count{ Listen::getCount(session, user->getId(), ScrobblingBackend::Internal, track.getId()) };
         EXPECT_EQ(count, 1);
@@ -905,7 +905,7 @@ TEST_F(DatabaseFixture, Listen_getCount_release)
 
     auto getReleaseListenCount{ [&]
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         return Listen::getCount(session, user->getId(), ScrobblingBackend::Internal, release.getId());
     } };
 
@@ -917,14 +917,14 @@ TEST_F(DatabaseFixture, Listen_getCount_release)
     EXPECT_EQ(getReleaseListenCount(), 0);
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track1.get().modify()->setRelease(release.get());
     }
 
     EXPECT_EQ(getReleaseListenCount(), 1);
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track2.get().modify()->setRelease(release.get());
     }
 
@@ -944,7 +944,7 @@ TEST_F(DatabaseFixture, Listen_getMostRecentTrack)
     ScopedUser user{ session, "MyUser" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto listen{ Listen::getMostRecentListen(session, user->getId(), ScrobblingBackend::Internal, track.getId()) };
         EXPECT_FALSE(listen);
@@ -954,7 +954,7 @@ TEST_F(DatabaseFixture, Listen_getMostRecentTrack)
     ScopedListen listen1{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime1 };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto listen{ Listen::getMostRecentListen(session, user->getId(), ScrobblingBackend::Internal, track.getId()) };
         EXPECT_TRUE(listen);
@@ -965,7 +965,7 @@ TEST_F(DatabaseFixture, Listen_getMostRecentTrack)
     ScopedListen listen2{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime2 };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto listen{ Listen::getMostRecentListen(session, user->getId(), ScrobblingBackend::Internal, track.getId()) };
         EXPECT_TRUE(listen);
@@ -976,7 +976,7 @@ TEST_F(DatabaseFixture, Listen_getMostRecentTrack)
     ScopedListen listen3{ session, user.lockAndGet(), track.lockAndGet(), ScrobblingBackend::Internal, dateTime3 };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto listen{ Listen::getMostRecentListen(session, user->getId(), ScrobblingBackend::Internal, track.getId()) };
         EXPECT_TRUE(listen);
@@ -994,7 +994,7 @@ TEST_F(DatabaseFixture, Listen_getRecentTracks_multi)
     ScopedListen listen1{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getRecentTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -1004,7 +1004,7 @@ TEST_F(DatabaseFixture, Listen_getRecentTracks_multi)
 
     ScopedListen listen2{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(1) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getRecentTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -1015,7 +1015,7 @@ TEST_F(DatabaseFixture, Listen_getRecentTracks_multi)
 
     ScopedListen listen3{ session, user.lockAndGet(), track2.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(2) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getRecentTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -1026,7 +1026,7 @@ TEST_F(DatabaseFixture, Listen_getRecentTracks_multi)
 
     ScopedListen listen4{ session, user.lockAndGet(), track1.lockAndGet(), ScrobblingBackend::Internal, dateTime.addSecs(-1) };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getRecentTracks(session, user->getId(), ScrobblingBackend::Internal, {}) };
         EXPECT_EQ(tracks.moreResults, false);
@@ -1046,18 +1046,18 @@ TEST_F(DatabaseFixture, Listen_getRecentTracks_cluster)
     ScopedCluster cluster{ session, clusterType.lockAndGet(), "MyCluster" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getRecentTracks(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}) };
         EXPECT_EQ(tracks.results.size(), 0);
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         cluster.get().modify()->addTrack(track.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Listen::getRecentTracks(session, user->getId(), ScrobblingBackend::Internal, {cluster.getId()}) };
         EXPECT_EQ(tracks.results.size(), 1);

src/libs/services/database/test/Release.cpp

@@ -24,7 +24,7 @@ using namespace Database;
 TEST_F(DatabaseFixture, Release)
 {
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_EQ(Release::getCount(session), 0);
         EXPECT_EQ(Release::getCount(session, Release::FindParameters{}), 0);
@@ -35,7 +35,7 @@ TEST_F(DatabaseFixture, Release)
     ScopedRelease release{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_EQ(Release::getCount(session), 1);
         EXPECT_EQ(Release::getCount(session, Release::FindParameters{}), 1);
@@ -79,7 +79,7 @@ TEST_F(DatabaseFixture, Release_singleTrack)
     {
         ScopedTrack track{ session, "MyTrack" };
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             track.get().modify()->setRelease(release.get());
             track.get().modify()->setName("MyTrackName");
@@ -87,7 +87,7 @@ TEST_F(DatabaseFixture, Release_singleTrack)
         }
 
         {
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
             EXPECT_TRUE(Release::findOrphanIds(session).results.empty());
 
             const auto tracks{ Track::findIds(session, Track::FindParameters {}.setRelease(release.getId())) };
@@ -96,32 +96,32 @@ TEST_F(DatabaseFixture, Release_singleTrack)
         }
 
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             ASSERT_TRUE(track->getRelease());
             EXPECT_EQ(track->getRelease()->getId(), release.getId());
         }
 
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
             auto tracks{ Track::findIds(session, Track::FindParameters{}.setName("MyTrackName").setReleaseName("MyReleaseName")) };
             ASSERT_EQ(tracks.results.size(), 1);
             EXPECT_EQ(tracks.results.front(), track.getId());
         }
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
             auto tracks{ Track::findIds(session, Track::FindParameters{}.setName("MyTrackName").setReleaseName("MyReleaseFoo")) };
             EXPECT_EQ(tracks.results.size(), 0);
         }
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
             auto tracks{ Track::findIds(session, Track::FindParameters{}.setName("MyTrackFoo").setReleaseName("MyReleaseName")) };
             EXPECT_EQ(tracks.results.size(), 0);
         }
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         const auto tracks{ Track::findIds(session, Track::FindParameters {}.setRelease(release.getId())) };
         EXPECT_TRUE(tracks.results.empty());
@@ -150,7 +150,7 @@ TEST_F(DatabaseFixture, MulitpleReleaseSearchByName)
     ScopedTrack track6{ session, "MyTrack" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track1.get().modify()->setRelease(release1.get());
         track2.get().modify()->setRelease(release2.get());
@@ -161,7 +161,7 @@ TEST_F(DatabaseFixture, MulitpleReleaseSearchByName)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             const auto releases{ Release::findIds(session, Release::FindParameters {}.setKeywords({"Release"})) };
@@ -203,33 +203,33 @@ TEST_F(DatabaseFixture, MultiTracksSingleReleaseTotalDiscTrack)
     ScopedRelease release1{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_FALSE(release1->getTotalDisc());
     }
 
     ScopedTrack track1{ session, "MyTrack" };
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track1.get().modify()->setRelease(release1.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_FALSE(release1->getTotalDisc());
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track1.get().modify()->setTotalTrack(36);
         release1.get().modify()->setTotalDisc(6);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         ASSERT_TRUE(track1->getTotalTrack());
         EXPECT_EQ(*track1->getTotalTrack(), 36);
@@ -239,7 +239,7 @@ TEST_F(DatabaseFixture, MultiTracksSingleReleaseTotalDiscTrack)
 
     ScopedTrack track2{ session, "MyTrack2" };
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track2.get().modify()->setRelease(release1.get());
         track2.get().modify()->setTotalTrack(37);
@@ -247,7 +247,7 @@ TEST_F(DatabaseFixture, MultiTracksSingleReleaseTotalDiscTrack)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         ASSERT_TRUE(track1->getTotalTrack());
         EXPECT_EQ(*track1->getTotalTrack(), 36);
@@ -257,21 +257,21 @@ TEST_F(DatabaseFixture, MultiTracksSingleReleaseTotalDiscTrack)
 
     ScopedRelease release2{ session, "MyRelease2" };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_FALSE(release2->getTotalDisc());
     }
 
     ScopedTrack track3{ session, "MyTrack3" };
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track3.get().modify()->setRelease(release2.get());
         track3.get().modify()->setTotalTrack(7);
         release2.get().modify()->setTotalDisc(5);
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         ASSERT_TRUE(track1->getTotalTrack());
         EXPECT_EQ(*track1->getTotalTrack(), 36);
@@ -295,14 +295,14 @@ TEST_F(DatabaseFixture, MultiTracksSingleReleaseFirstTrack)
     ScopedTrack track2B{ session, "MyTrack2B" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_TRUE(Track::findIds(session, Track::FindParameters{}.setRelease(release1.getId())).results.empty());
         EXPECT_TRUE(Track::findIds(session, Track::FindParameters{}.setRelease(release2.getId())).results.empty());
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track1A.get().modify()->setRelease(release1.get());
         track1B.get().modify()->setRelease(release1.get());
@@ -319,7 +319,7 @@ TEST_F(DatabaseFixture, MultiTracksSingleReleaseFirstTrack)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             const auto tracks{ Track::findIds(session, Track::FindParameters {}.setRelease(release1.getId()).setSortMethod(TrackSortMethod::Release)) };
@@ -348,14 +348,14 @@ TEST_F(DatabaseFixture, MultiTracksSingleReleaseDate)
     ScopedTrack track2B{ session, "MyTrack2B" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setDateRange(DateRange::fromYearRange(0, 3000))) };
         EXPECT_EQ(releases.results.size(), 0);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track1A.get().modify()->setRelease(release1.get());
         track1B.get().modify()->setRelease(release1.get());
@@ -373,7 +373,7 @@ TEST_F(DatabaseFixture, MultiTracksSingleReleaseDate)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Release::findIds(session, Release::FindParameters {}.setDateRange(DateRange::fromYearRange(1950, 2000))) };
         ASSERT_EQ(releases.results.size(), 1);
@@ -396,25 +396,25 @@ TEST_F(DatabaseFixture, Release_writtenAfter)
     const Wt::WDateTime dateTime{ Wt::WDate {1950, 1, 1}, Wt::WTime {12, 30, 20} };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setLastWriteTime(dateTime);
         track.get().modify()->setRelease(release.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         const auto releases{ Release::findIds(session, Release::FindParameters {}) };
         EXPECT_EQ(releases.results.size(), 1);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setWrittenAfter(dateTime.addSecs(-1))) };
         EXPECT_EQ(releases.results.size(), 1);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setWrittenAfter(dateTime.addSecs(+1))) };
         EXPECT_EQ(releases.results.size(), 0);
     }
@@ -427,12 +427,12 @@ TEST_F(DatabaseFixture, Release_artist)
     ScopedArtist artist{ session, "MyArtist" };
     ScopedArtist artist2{ session, "MyArtist2" };
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setRelease(release.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Release::findIds(session, Release::FindParameters {}.setArtist(artist.getId(), {TrackArtistLinkType::Artist})) };
         EXPECT_EQ(releases.results.size(), 0);
@@ -442,7 +442,7 @@ TEST_F(DatabaseFixture, Release_artist)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         TrackArtistLink::create(session, track.get(), artist.get(), TrackArtistLinkType::Artist);
 
         auto releases{ Release::findIds(session, Release::FindParameters {}.setArtist(artist.getId(), {TrackArtistLinkType::Artist})) };
@@ -488,40 +488,40 @@ TEST_F(DatabaseFixture, Release_getDiscCount)
     ScopedTrack track2{ session, "MyTrack2" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(release.get()->getDiscCount(), 0);
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setRelease(release.get());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(release.get()->getDiscCount(), 0);
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setDiscNumber(5);
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(release.get()->getDiscCount(), 1);
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track2.get().modify()->setRelease(release.get());
         track2.get().modify()->setDiscNumber(5);
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(release.get()->getDiscCount(), 1);
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track2.get().modify()->setDiscNumber(6);
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(release.get()->getDiscCount(), 2);
     }
 }
@@ -531,19 +531,19 @@ TEST_F(DatabaseFixture, Release_releaseType)
     ScopedRelease release{ session, "MyRelease" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(release.get()->getPrimaryType(), std::nullopt);
         EXPECT_EQ(release.get()->getSecondaryTypes(), EnumSet<ReleaseTypeSecondary> {});
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         release.get().modify()->setPrimaryType({ ReleaseTypePrimary::Album });
         release.get().modify()->setSecondaryTypes({ ReleaseTypeSecondary::Compilation });
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(release.get()->getPrimaryType(), ReleaseTypePrimary::Album);
         EXPECT_TRUE(release.get()->getSecondaryTypes().contains(ReleaseTypeSecondary::Compilation));
     }
@@ -565,7 +565,7 @@ TEST_F(DatabaseFixture, Release_sortMethod)
     ASSERT_GT(release2Date, release1OriginalDate);
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         track1.get().modify()->setRelease(release1.get());
         track1.get().modify()->setOriginalDate(release1OriginalDate);
@@ -576,7 +576,7 @@ TEST_F(DatabaseFixture, Release_sortMethod)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setSortMethod(ReleaseSortMethod::Name)) };
         ASSERT_EQ(releases.results.size(), 2);
@@ -585,14 +585,14 @@ TEST_F(DatabaseFixture, Release_sortMethod)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setSortMethod(ReleaseSortMethod::Random)) };
         ASSERT_EQ(releases.results.size(), 2);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setSortMethod(ReleaseSortMethod::Date)) };
         ASSERT_EQ(releases.results.size(), 2);
@@ -601,7 +601,7 @@ TEST_F(DatabaseFixture, Release_sortMethod)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setSortMethod(ReleaseSortMethod::OriginalDate)) };
         ASSERT_EQ(releases.results.size(), 2);
@@ -609,7 +609,7 @@ TEST_F(DatabaseFixture, Release_sortMethod)
         EXPECT_EQ(releases.results.back(), release2.getId());
     }
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto releases{ Release::findIds(session, Release::FindParameters {}.setSortMethod(ReleaseSortMethod::OriginalDateDesc)) };
         ASSERT_EQ(releases.results.size(), 2);
@@ -627,14 +627,14 @@ TEST_F(DatabaseFixture, Release_meanBitrate)
 
     auto checkExpectedBitrate = [&](std::size_t bitrate)
         {
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
             EXPECT_EQ(release1->getMeanBitrate(), bitrate);
         };
 
     checkExpectedBitrate(0);
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track1.get().modify()->setBitrate(128);
         track1.get().modify()->setRelease(release1.get());
     }
@@ -642,14 +642,14 @@ TEST_F(DatabaseFixture, Release_meanBitrate)
     checkExpectedBitrate(128);
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track2.get().modify()->setBitrate(256);
         track2.get().modify()->setRelease(release1.get());
     }
     checkExpectedBitrate(192);
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track3.get().modify()->setBitrate(0);
         track3.get().modify()->setRelease(release1.get());
     }

src/libs/services/database/test/StarredArtist.cpp

@@ -31,7 +31,7 @@ TEST_F(DatabaseFixture, StarredArtist)
     ScopedUser user2{ session, "MyUser2" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto starredArtist{ StarredArtist::find(session, artist->getId(), user->getId(), FeedbackBackend::Internal) };
         EXPECT_FALSE(starredArtist);
@@ -43,7 +43,7 @@ TEST_F(DatabaseFixture, StarredArtist)
 
     ScopedStarredArtist starredArtist{ session, artist.lockAndGet(), user.lockAndGet(), FeedbackBackend::Internal };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto gotArtist{ StarredArtist::find(session, artist->getId(), user->getId(), FeedbackBackend::Internal) };
         EXPECT_EQ(gotArtist->getId(), starredArtist->getId());
@@ -51,7 +51,7 @@ TEST_F(DatabaseFixture, StarredArtist)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Artist::findIds(session, Artist::FindParameters {}) };
         EXPECT_EQ(artists.results.size(), 1);
@@ -64,24 +64,24 @@ TEST_F(DatabaseFixture, StarredArtist)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         user.get().modify()->setFeedbackBackend(FeedbackBackend::ListenBrainz);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto gotArtist{ StarredArtist::find(session, artist->getId(), user->getId()) };
         EXPECT_EQ(gotArtist, Artist::pointer{});
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         user.get().modify()->setFeedbackBackend(FeedbackBackend::Internal);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         auto gotArtist{ StarredArtist::find(session, artist->getId(), user->getId()) };
         EXPECT_EQ(gotArtist->getId(), starredArtist->getId());
     }
@@ -94,7 +94,7 @@ TEST_F(DatabaseFixture, StarredArtist_PendingDestroy)
     ScopedStarredArtist starredArtist{ session, artist.lockAndGet(), user.lockAndGet(), FeedbackBackend::Internal };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto artists{ Artist::findIds(session, Artist::FindParameters {}.setStarringUser(user.getId(), FeedbackBackend::Internal)) };
         EXPECT_EQ(artists.results.size(), 1);
@@ -117,14 +117,14 @@ TEST_F(DatabaseFixture, StarredArtist_dateTime)
     const Wt::WDateTime dateTime{ Wt::WDate {1950, 1, 2}, Wt::WTime {12, 30, 1} };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto artists{ Artist::find(session, Artist::FindParameters {}.setStarringUser(user.getId(), FeedbackBackend::Internal)) };
         EXPECT_EQ(artists.results.size(), 2);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         starredArtist1.get().modify()->setDateTime(dateTime);
         starredArtist2.get().modify()->setDateTime(dateTime.addSecs(-1));
@@ -135,7 +135,7 @@ TEST_F(DatabaseFixture, StarredArtist_dateTime)
         EXPECT_EQ(artists.results[1], starredArtist2->getArtist()->getId());
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         starredArtist1.get().modify()->setDateTime(dateTime);
         starredArtist2.get().modify()->setDateTime(dateTime.addSecs(1));

src/libs/services/database/test/StarredRelease.cpp

@@ -31,7 +31,7 @@ TEST_F(DatabaseFixture, StarredRelease)
     ScopedUser user2{ session, "MyUser2" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto starredRelease{ StarredRelease::find(session, release->getId(), user->getId(), FeedbackBackend::Internal) };
         EXPECT_FALSE(starredRelease);
@@ -43,7 +43,7 @@ TEST_F(DatabaseFixture, StarredRelease)
 
     ScopedStarredRelease starredRelease{ session, release.lockAndGet(), user.lockAndGet(), FeedbackBackend::Internal };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto gotRelease{ StarredRelease::find(session, release->getId(), user->getId(), FeedbackBackend::Internal) };
         EXPECT_EQ(gotRelease->getId(), starredRelease->getId());
@@ -51,7 +51,7 @@ TEST_F(DatabaseFixture, StarredRelease)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Release::find(session, Release::FindParameters {}) };
         EXPECT_EQ(releases.results.size(), 1);
@@ -64,12 +64,12 @@ TEST_F(DatabaseFixture, StarredRelease)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         user.get().modify()->setFeedbackBackend(FeedbackBackend::ListenBrainz);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto gotRelease{ StarredRelease::find(session, release->getId(), user->getId()) };
         EXPECT_EQ(gotRelease, StarredRelease::pointer{});
@@ -83,7 +83,7 @@ TEST_F(DatabaseFixture, Starredrelease_PendingDestroy)
     ScopedStarredRelease starredRelease{ session, release.lockAndGet(), user.lockAndGet(), FeedbackBackend::Internal };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto releases{ Release::find(session, Release::FindParameters {}.setStarringUser(user.getId(), FeedbackBackend::Internal)) };
         EXPECT_EQ(releases.results.size(), 1);
@@ -106,14 +106,14 @@ TEST_F(DatabaseFixture, StarredRelease_dateTime)
     const Wt::WDateTime dateTime{ Wt::WDate {1950, 1, 2}, Wt::WTime {12, 30, 1} };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto releases{ Release::findIds(session, Release::FindParameters {}.setStarringUser(user.getId(), FeedbackBackend::Internal)) };
         EXPECT_EQ(releases.results.size(), 2);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         starredRelease1.get().modify()->setDateTime(dateTime);
         starredRelease2.get().modify()->setDateTime(dateTime.addSecs(-1));
@@ -124,7 +124,7 @@ TEST_F(DatabaseFixture, StarredRelease_dateTime)
         EXPECT_EQ(releases.results[1], starredRelease2->getRelease()->getId());
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         starredRelease1.get().modify()->setDateTime(dateTime);
         starredRelease2.get().modify()->setDateTime(dateTime.addSecs(1));

src/libs/services/database/test/StarredTrack.cpp

@@ -31,7 +31,7 @@ TEST_F(DatabaseFixture, StarredTrack)
     ScopedUser user2{ session, "MyUser2" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction {session.createReadTransaction()};
 
         auto starredTrack{ StarredTrack::find(session, track->getId(), user->getId(), FeedbackBackend::Internal) };
         EXPECT_FALSE(starredTrack);
@@ -43,7 +43,7 @@ TEST_F(DatabaseFixture, StarredTrack)
 
     ScopedStarredTrack starredTrack{ session, track.lockAndGet(), user.lockAndGet(), FeedbackBackend::Internal };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction {session.createReadTransaction()};
 
         auto gotTrack{ StarredTrack::find(session, track->getId(), user->getId(), FeedbackBackend::Internal) };
         EXPECT_EQ(gotTrack->getId(), starredTrack->getId());
@@ -51,7 +51,7 @@ TEST_F(DatabaseFixture, StarredTrack)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction {session.createReadTransaction()};
 
         auto tracks{ Track::findIds(session, Track::FindParameters {}) };
         EXPECT_EQ(tracks.results.size(), 1);
@@ -64,12 +64,12 @@ TEST_F(DatabaseFixture, StarredTrack)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         user.get().modify()->setFeedbackBackend(FeedbackBackend::ListenBrainz);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto gotRelease{ StarredTrack::find(session, track->getId(), user->getId()) };
         EXPECT_EQ(gotRelease, StarredTrack::pointer{});
@@ -83,7 +83,7 @@ TEST_F(DatabaseFixture, Starredtrack_PendingDestroy)
     ScopedStarredTrack starredTrack{ session, track.lockAndGet(), user.lockAndGet(), FeedbackBackend::Internal };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction {session.createWriteTransaction()};
 
         auto tracks{ Track::findIds(session, Track::FindParameters {}.setStarringUser(user.getId(), FeedbackBackend::Internal)) };
         EXPECT_EQ(tracks.results.size(), 1);
@@ -106,14 +106,14 @@ TEST_F(DatabaseFixture, StarredTrack_dateTime)
     const Wt::WDateTime dateTime{ Wt::WDate {1950, 1, 2}, Wt::WTime {12, 30, 1} };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction {session.createReadTransaction()};
 
         auto tracks{ Track::findIds(session, Track::FindParameters {}.setStarringUser(user.getId(), FeedbackBackend::Internal)) };
         EXPECT_EQ(tracks.results.size(), 2);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction {session.createWriteTransaction()};
 
         starredTrack1.get().modify()->setDateTime(dateTime);
         starredTrack2.get().modify()->setDateTime(dateTime.addSecs(-1));
@@ -124,7 +124,7 @@ TEST_F(DatabaseFixture, StarredTrack_dateTime)
         EXPECT_EQ(tracks.results[1], starredTrack2->getTrack()->getId());
     }
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction {session.createWriteTransaction()};
 
         starredTrack1.get().modify()->setDateTime(dateTime);
         starredTrack2.get().modify()->setDateTime(dateTime.addSecs(1));

src/libs/services/database/test/Track.cpp

@@ -26,7 +26,7 @@ using namespace Database;
 TEST_F(DatabaseFixture, Track)
 {
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(Track::find(session, Track::FindParameters{}).results.size(), 0);
         EXPECT_EQ(Track::findIds(session, Track::FindParameters{}).results.size(), 0);
         EXPECT_EQ(Track::getCount(session), 0);
@@ -42,7 +42,7 @@ TEST_F(DatabaseFixture, Track)
     ScopedTrack track{ session, "MyTrackFile" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_EQ(Track::find(session, Track::FindParameters{}).results.size(), 1);
         EXPECT_EQ(Track::getCount(session), 1);
@@ -69,7 +69,7 @@ TEST_F(DatabaseFixture, MultipleTracks)
     ScopedTrack track2{ session, "MyTrackFile2" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         EXPECT_TRUE(track1.getId() != track2.getId());
         EXPECT_TRUE(track1.get() != track2.get());
@@ -87,7 +87,7 @@ TEST_F(DatabaseFixture, MultipleTracksSearchByFilter)
     ScopedTrack track6{ session, "" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track1.get().modify()->setName("MyTrack");
         track2.get().modify()->setName("MyTrack%");
         track3.get().modify()->setName("MyTrack%Foo");
@@ -97,7 +97,7 @@ TEST_F(DatabaseFixture, MultipleTracksSearchByFilter)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         {
             const auto tracks{ Track::findIds(session, Track::FindParameters {}.setKeywords({"Track"})) };
@@ -128,19 +128,19 @@ TEST_F(DatabaseFixture, Track_date)
     ScopedTrack track{ session, "MyTrack" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(track->getYear(), std::nullopt);
         EXPECT_EQ(track->getOriginalYear(), std::nullopt);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setDate(Wt::WDate{ 1995, 5, 5 });
         track.get().modify()->setOriginalDate(Wt::WDate{ 1994, 2, 2 });
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(track->getYear(), 1995);
         EXPECT_EQ(track->getOriginalYear(), 1994);
     }
@@ -153,24 +153,24 @@ TEST_F(DatabaseFixture, Track_writtenAfter)
     const Wt::WDateTime dateTime{ Wt::WDate {1950, 1, 1}, Wt::WTime {12, 30, 20} };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         track.get().modify()->setLastWriteTime(dateTime);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         const auto tracks{ Track::findIds(session, Track::FindParameters {}) };
         EXPECT_EQ(tracks.results.size(), 1);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         const auto tracks{ Track::findIds(session, Track::FindParameters {}.setWrittenAfter(dateTime.addSecs(-1))) };
         EXPECT_EQ(tracks.results.size(), 1);
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         const auto tracks{ Track::findIds(session, Track::FindParameters {}.setWrittenAfter(dateTime.addSecs(+1))) };
         EXPECT_EQ(tracks.results.size(), 0);
     }

src/libs/services/database/test/TrackBookmark.cpp

@@ -31,21 +31,21 @@ TEST_F(DatabaseFixture, TrackBookmark)
 	ScopedUser user {session, "MyUser"};
 
 	{
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 		EXPECT_EQ(TrackBookmark::getCount(session), 0);
 	}
 
 	ScopedTrackBookmark bookmark {session, user.lockAndGet(), track.lockAndGet()};
 
 	{
-		auto transaction {session.createUniqueTransaction()};
+		auto transaction {session.createWriteTransaction()};
 
 		bookmark.get().modify()->setComment("MyComment");
 		bookmark.get().modify()->setOffset(std::chrono::milliseconds {5});
 	}
 
 	{
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		EXPECT_EQ(TrackBookmark::getCount(session), 1);
 
@@ -54,7 +54,7 @@ TEST_F(DatabaseFixture, TrackBookmark)
 		EXPECT_EQ(bookmarks.results.front(), bookmark.getId());
 	}
 	{
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		auto userBookmark {TrackBookmark::find(session, user.getId(), track.getId())};
 		ASSERT_TRUE(userBookmark);

src/libs/services/database/test/TrackFeatures.cpp

@@ -31,14 +31,14 @@ TEST_F(DatabaseFixture, TrackFeatures)
 	ScopedUser user {session, "MyUser"};
 
 	{
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 		EXPECT_EQ(TrackFeatures::getCount(session), 0);
 	}
 
 	ScopedTrackFeatures trackFeatures {session, track.lockAndGet(), ""};
 
 	{
-		auto transaction {session.createUniqueTransaction()};
+		auto transaction {session.createWriteTransaction()};
 		EXPECT_EQ(TrackFeatures::getCount(session), 1);
 
 		auto allTrackFeatures {TrackFeatures::find(session)};

src/libs/services/database/test/TrackList.cpp

@@ -27,14 +27,14 @@ TEST_F(DatabaseFixture, SingleTrackList)
 {
     ScopedUser user{ session, "MyUser" };
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(TrackList::getCount(session), 0);
     }
 
     ScopedTrackList trackList{ session, "MytrackList", TrackListType::Playlist, false, user.lockAndGet() };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         EXPECT_EQ(TrackList::getCount(session), 1);
     }
 }
@@ -47,7 +47,7 @@ TEST_F(DatabaseFixture, SingleTrackListSingleTrack)
     ScopedTrack track{ session, "MyTrack" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Track::findIds(session, Track::FindParameters {}.setTrackList(trackList1.getId())) };
         EXPECT_EQ(tracks.results.size(), 0);
@@ -57,13 +57,13 @@ TEST_F(DatabaseFixture, SingleTrackListSingleTrack)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         session.create<TrackListEntry>(track.get(), trackList1.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto tracks{ Track::findIds(session, Track::FindParameters {}.setTrackList(trackList1.getId())) };
         ASSERT_EQ(tracks.results.size(), 1);
@@ -82,7 +82,7 @@ TEST_F(DatabaseFixture, TrackList_SortMethod)
     ScopedTrack track{ session, "MyTrack" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto trackLists{ TrackList::find(session, TrackList::FindParameters {}.setSortMethod(TrackListSortMethod::Name)) };
         ASSERT_EQ(trackLists.results.size(), 2);
@@ -91,14 +91,14 @@ TEST_F(DatabaseFixture, TrackList_SortMethod)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         trackList1.get().modify()->setLastModifiedDateTime(Wt::WDateTime{ Wt::WDate {1900,1,1} });
         trackList2.get().modify()->setLastModifiedDateTime(Wt::WDateTime{ Wt::WDate {1900,1,2} });
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto trackLists{ TrackList::find(session, TrackList::FindParameters {}.setSortMethod(TrackListSortMethod::LastModifiedDesc)) };
         ASSERT_EQ(trackLists.results.size(), 2);
@@ -107,14 +107,14 @@ TEST_F(DatabaseFixture, TrackList_SortMethod)
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         trackList1.get().modify()->setLastModifiedDateTime(Wt::WDateTime{ Wt::WDate {1900,1,2} });
         trackList2.get().modify()->setLastModifiedDateTime(Wt::WDateTime{ Wt::WDate {1900,1,1} });
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const auto trackLists{ TrackList::find(session, TrackList::FindParameters {}.setSortMethod(TrackListSortMethod::LastModifiedDesc)) };
         ASSERT_EQ(trackLists.results.size(), 2);
@@ -133,12 +133,12 @@ TEST_F(DatabaseFixture, SingleTrackListMultipleTrack)
     {
         tracks.emplace_back(session, "MyTrack" + std::to_string(i));
 
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         session.create<TrackListEntry>(tracks.back().get(), trackList.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         ASSERT_EQ(trackList->getCount(), tracks.size());
         const auto trackIds{ trackList->getTrackIds() };
@@ -161,21 +161,21 @@ TEST_F(DatabaseFixture, SingleTrackListSingleTrackWithCluster)
     ScopedTrack track{ session, "MyTrack" };
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto trackLists{ TrackList::find(session, TrackList::FindParameters {}.setClusters({cluster.getId()})) };
         EXPECT_EQ(trackLists.results.size(), 0);
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         session.create<TrackListEntry>(track.get(), trackList1.get());
         cluster.get().modify()->addTrack(track.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         auto trackLists{ TrackList::find(session, TrackList::FindParameters {}.setClusters({cluster.getId()})) };
         ASSERT_EQ(trackLists.results.size(), 1);
@@ -191,24 +191,24 @@ TEST_F(DatabaseFixture, SingleTrackList_getEntries)
     ScopedTrack track2{ session, "MyTrack" };
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         session.create<TrackListEntry>(track1.get(), trackList.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto entries{ trackList.get()->getEntries() };
         ASSERT_EQ(entries.size(), 1);
         EXPECT_EQ(entries.front()->getTrack()->getId(), track1.getId());
     }
 
     {
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
         session.create<TrackListEntry>(track2.get(), trackList.get());
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto entries{ trackList.get()->getEntries() };
         ASSERT_EQ(entries.size(), 2);
         EXPECT_EQ(entries[0]->getTrack()->getId(), track1.getId());
@@ -216,7 +216,7 @@ TEST_F(DatabaseFixture, SingleTrackList_getEntries)
     }
 
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         auto entries{ trackList.get()->getEntries(Range {1, 1}) };
         ASSERT_EQ(entries.size(), 1);
         EXPECT_EQ(entries[0]->getTrack()->getId(), track2.getId());

src/libs/services/feedback/impl/FeedbackService.cpp

@@ -60,7 +60,7 @@ namespace Feedback
         std::optional<Database::FeedbackBackend> feedbackBackend;
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         if (const User::pointer user{ User::find(session, userId) })
             feedbackBackend = user->getFeedbackBackend();
 
@@ -101,7 +101,7 @@ namespace Feedback
         searchParams.setRange(params.range);
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         return Artist::findIds(session, searchParams);
     }
@@ -139,7 +139,7 @@ namespace Feedback
         searchParams.setRange(params.range);
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         return Release::findIds(session, searchParams);
     }
@@ -177,7 +177,7 @@ namespace Feedback
         searchParams.setRange(params.range);
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         return Track::findIds(session, searchParams);
     }

src/libs/services/feedback/impl/FeedbackService.impl.hpp

@@ -37,7 +37,7 @@ namespace Feedback
         typename StarredObjType::IdType starredObjId;
         {
             Session& session{ _db.getTLSSession() };
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             typename StarredObjType::pointer starredObj{ StarredObjType::find(session, objId, userId, *backend) };
             if (!starredObj)
@@ -68,7 +68,7 @@ namespace Feedback
         typename StarredObjType::IdType starredObjId;
         {
             Session& session{ _db.getTLSSession() };
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             typename StarredObjType::pointer starredObj{ StarredObjType::find(session, objId, userId, *backend) };
             if (!starredObj)
@@ -83,7 +83,7 @@ namespace Feedback
     bool FeedbackService::isStarred(UserId userId, ObjIdType objId)
     {
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         typename StarredObjType::pointer starredObj{ StarredObjType::find(session, objId, userId) };
         return starredObj && (starredObj->getSyncState() != SyncState::PendingRemove);
@@ -93,7 +93,7 @@ namespace Feedback
     Wt::WDateTime FeedbackService::getStarredDateTime(UserId userId, ObjIdType objId)
     {
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         typename StarredObjType::pointer starredObj{ StarredObjType::find(session, objId, userId) };
         if (starredObj && (starredObj->getSyncState() != SyncState::PendingRemove))

src/libs/services/feedback/impl/internal/InternalBackend.cpp

@@ -32,7 +32,7 @@ namespace Feedback
         template <typename StarredObjType>
         void onStarred(Database::Session& session, typename StarredObjType::IdType id)
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             if (auto starredObj{ StarredObjType::find(session, id) })
                 starredObj.modify()->setSyncState(Database::SyncState::Synchronized);
@@ -41,7 +41,7 @@ namespace Feedback
         template <typename StarredObjType>
         void onUnstarred(Database::Session& session, typename StarredObjType::IdType id)
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             if (auto starredObj{ StarredObjType::find(session, id) })
                 starredObj.remove();

src/libs/services/feedback/impl/listenbrainz/FeedbacksSynchronizer.cpp

@@ -77,7 +77,7 @@ namespace Feedback::ListenBrainz
         {
             Database::Session& session{ _db.getTLSSession() };
 
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             Database::StarredTrack::pointer starredTrack{ Database::StarredTrack::find(session, starredTrackId) };
             if (!starredTrack)
@@ -151,7 +151,7 @@ namespace Feedback::ListenBrainz
         assert(_strand.running_in_this_thread());
 
         Database::Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         Database::StarredTrack::pointer starredTrack{ Database::StarredTrack::find(session, starredTrackId) };
         if (!starredTrack)
@@ -202,7 +202,7 @@ namespace Feedback::ListenBrainz
             {
                 Database::Session& session {_db.getTLSSession()};
 
-                auto transaction {session.createSharedTransaction()};
+                auto transaction {session.createReadTransaction()};
 
                 StarredTrack::FindParameters params;
                 params.setFeedbackBackend(Database::FeedbackBackend::ListenBrainz, scrobblingState)
@@ -277,7 +277,7 @@ namespace Feedback::ListenBrainz
         Database::RangeResults<Database::UserId> userIds;
         {
             Database::Session& session{ _db.getTLSSession() };
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
             userIds = Database::User::find(_db.getTLSSession(), Database::User::FindParameters{}.setFeedbackBackend(Database::FeedbackBackend::ListenBrainz));
         }
 
@@ -437,7 +437,7 @@ namespace Feedback::ListenBrainz
         TrackId trackId;
 
         {
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
             const std::vector<Track::pointer> tracks{ Track::findByRecordingMBID(session, feedback.recordingMBID) };
             if (tracks.size() > 1)
             {
@@ -463,7 +463,7 @@ namespace Feedback::ListenBrainz
         {
             LOG(DEBUG) << "Importing feedback '" << feedback << "'";
 
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             const Track::pointer track{ Track::find(session, trackId) };
             if (!track)

src/libs/services/feedback/impl/listenbrainz/ListenBrainzBackend.cpp

@@ -37,7 +37,7 @@ namespace Feedback::ListenBrainz
         template <typename StarredObjType>
         void onStarred(Database::Session& session, typename StarredObjType::IdType id)
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             if (auto starredObj{ StarredObjType::find(session, id) })
             {
@@ -49,7 +49,7 @@ namespace Feedback::ListenBrainz
         template <typename StarredObjType>
         void onUnstarred(Database::Session& session, typename StarredObjType::IdType id)
         {
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             if (auto starredObj{ StarredObjType::find(session, id) })
                 starredObj.remove();

src/libs/services/feedback/impl/listenbrainz/Utils.cpp

@@ -29,7 +29,7 @@ namespace Feedback::ListenBrainz::Utils
 {
     std::optional<UUID> getListenBrainzToken(Database::Session& session, Database::UserId userId)
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const Database::User::pointer user{ Database::User::find(session, userId) };
         if (!user)

src/libs/services/recommendation/impl/PlaylistGeneratorService.cpp

@@ -100,7 +100,7 @@ namespace Recommendation
         TrackContainer tracks;
 
         Session& dbSession{ _db.getTLSSession() };
-        auto transaction{ dbSession.createSharedTransaction() };
+        auto transaction{ dbSession.createReadTransaction() };
 
         Track::FindParameters params;
         params.setTrackList(tracklistId);

src/libs/services/recommendation/impl/RecommendationService.cpp

@@ -37,7 +37,7 @@ namespace Recommendation
     {
         Database::ScanSettings::SimilarityEngineType getSimilarityEngineType(Database::Session& session)
         {
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             return Database::ScanSettings::get(session)->getSimilarityEngineType();
         }

src/libs/services/recommendation/impl/clusters/ClustersEngine.cpp

@@ -42,7 +42,7 @@ namespace Recommendation {
             return {};
 
         Session& dbSession{ _db.getTLSSession() };
-        auto transaction{ dbSession.createSharedTransaction() };
+        auto transaction{ dbSession.createReadTransaction() };
 
         const auto similarTrackIds{ Track::findSimilarTrackIds(dbSession, trackIds, Range {0, maxCount}) };
         return std::move(similarTrackIds.results);
@@ -56,7 +56,7 @@ namespace Recommendation {
 
         {
             Session& dbSession{ _db.getTLSSession() };
-            auto transaction{ dbSession.createSharedTransaction() };
+            auto transaction{ dbSession.createReadTransaction() };
 
             const TrackList::pointer trackList{ TrackList::find(dbSession, tracklistId) };
             if (!trackList)
@@ -78,7 +78,7 @@ namespace Recommendation {
 
         {
             Session& dbSession{ _db.getTLSSession() };
-            auto transaction{ dbSession.createSharedTransaction() };
+            auto transaction{ dbSession.createReadTransaction() };
 
             auto release{ Release::find(dbSession, releaseId) };
             if (!release)
@@ -98,7 +98,7 @@ namespace Recommendation {
             return {};
 
         Session& dbSession{ _db.getTLSSession() };
-        auto transaction{ dbSession.createSharedTransaction() };
+        auto transaction{ dbSession.createReadTransaction() };
 
         auto artist{ Artist::find(dbSession, artistId) };
         if (!artist)

src/libs/services/recommendation/impl/features/FeaturesEngine.cpp

@@ -117,7 +117,7 @@ FeaturesEngine::loadFromTraining(const TrainSettings& trainSettings, const Progr
 
 	RangeResults<TrackFeaturesId> trackFeaturesIds;
 	{
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		LMS_LOG(RECOMMENDATION, DEBUG) << "Getting Track features...";
 		trackFeaturesIds = TrackFeatures::find(session);
@@ -137,7 +137,7 @@ FeaturesEngine::loadFromTraining(const TrainSettings& trainSettings, const Progr
 		if (_loadCancelled)
 			return;
 
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		TrackFeatures::pointer trackFeatures {TrackFeatures::find(session, trackFeaturesId)};
 		if (!trackFeatures)
@@ -228,7 +228,7 @@ FeaturesEngine::findSimilarTracksFromTrackList(TrackListId trackListId, std::siz
 
 		Session& session {_db.getTLSSession()};
 
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		const TrackList::pointer trackList {TrackList::find(session, trackListId)};
 		if (trackList)
@@ -249,7 +249,7 @@ FeaturesEngine::findSimilarTracks(const std::vector<TrackId>& tracksIds, std::si
 
 	{
 		// Report only existing ids, as tracks may have been removed a long time ago (refreshing the SOM takes some time)
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		similarTrackIds.erase(std::remove_if(std::begin(similarTrackIds), std::end(similarTrackIds),
 			[&](TrackId trackId)
@@ -271,7 +271,7 @@ FeaturesEngine::getSimilarReleases(ReleaseId releaseId, std::size_t maxCount) co
 	if (!similarReleaseIds.empty())
 	{
 		// Report only existing ids
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		similarReleaseIds.erase(std::remove_if(std::begin(similarReleaseIds), std::end(similarReleaseIds),
 			[&](ReleaseId releaseId)
@@ -312,7 +312,7 @@ FeaturesEngine::getSimilarArtists(ArtistId artistId, EnumSet<TrackArtistLinkType
 	Session& session {_db.getTLSSession()};
 	{
 		// Report only existing ids
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		res.erase(std::remove_if(std::begin(res), std::end(res),
 			[&](ArtistId artistId)
@@ -384,7 +384,7 @@ FeaturesEngine::load(const SOM::Network& network, const TrackPositions& trackPos
 		if (_loadCancelled)
 			return;
 
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		const Track::pointer track {Track::find(session, trackId)};
 		if (!track)

src/libs/services/recommendation/impl/playlist-constraints/ConsecutiveArtists.cpp

@@ -80,7 +80,7 @@ namespace Recommendation::PlaylistGeneratorConstraint
 		ArtistContainer res;
 
 		Session& dbSession {_db.getTLSSession()};
-		auto transaction {dbSession.createSharedTransaction()};
+		auto transaction {dbSession.createReadTransaction()};
 
 		const Track::pointer track {Track::find(dbSession, trackId)};
 		if (!track)

src/libs/services/recommendation/impl/playlist-constraints/ConsecutiveReleases.cpp

@@ -61,7 +61,7 @@ namespace Recommendation::PlaylistGeneratorConstraint
 		using namespace Database;
 
 		Session& dbSession {_db.getTLSSession()};
-		auto transaction {dbSession.createSharedTransaction()};
+		auto transaction {dbSession.createReadTransaction()};
 
 		const Track::pointer track {Track::find(dbSession, trackId)};
 		if (!track)

src/libs/services/scanner/impl/ScanStepCheckDuplicatedDbFiles.cpp

@@ -35,7 +35,7 @@ namespace Scanner
 			return;
 
 		Session& session {_db.getTLSSession()};
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		const RangeResults<TrackId> tracks = Track::findIdsTrackMBIDDuplicates(session);
 		for (const TrackId trackId : tracks.results)

src/libs/services/scanner/impl/ScanStepComputeClusterStats.cpp

@@ -36,7 +36,7 @@ namespace Scanner
         Session& dbSession{ _db.getTLSSession() };
 
         const std::size_t clusterCount{ [&] {
-            auto transaction{ dbSession.createSharedTransaction() };
+            auto transaction{ dbSession.createReadTransaction() };
             return Cluster::getCount(dbSession);
             }() };
 
@@ -50,7 +50,7 @@ namespace Scanner
                     params.setRange(range);
 
                     {
-                        auto transaction{ dbSession.createSharedTransaction() };
+                        auto transaction{ dbSession.createReadTransaction() };
                         return std::move(Cluster::findIds(dbSession, params).results);
                     }
                 }() };
@@ -61,14 +61,14 @@ namespace Scanner
                     std::size_t releaseCount;
 
                     {
-                        auto transaction{ dbSession.createSharedTransaction() };
+                        auto transaction{ dbSession.createReadTransaction() };
 
                         trackCount = Cluster::computeTrackCount(dbSession, clusterId);
                         releaseCount = Cluster::computeReleaseCount(dbSession, clusterId);
                     }
 
                     {
-                        auto transaction{ dbSession.createUniqueTransaction() };
+                        auto transaction{ dbSession.createWriteTransaction() };
 
                         auto cluster{ Cluster::find(dbSession, clusterId) };
                         cluster.modify()->setTrackCount(trackCount);

src/libs/services/scanner/impl/ScanStepRemoveOrphanDbFiles.cpp

@@ -52,7 +52,7 @@ namespace Scanner
         std::size_t trackCount{};
 
         {
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
             trackCount = Track::getCount(session);
         }
         LMS_LOG(DBUPDATER, DEBUG) << trackCount << " tracks to be checked...";
@@ -68,7 +68,7 @@ namespace Scanner
             tracksToRemove.clear();
 
             {
-                auto transaction{ session.createSharedTransaction() };
+                auto transaction{ session.createReadTransaction() };
                 trackPaths = Track::findPaths(session, Range{ i, batchSize });
             }
 
@@ -85,7 +85,7 @@ namespace Scanner
 
             if (!tracksToRemove.empty())
             {
-                auto transaction{ session.createSharedTransaction() };
+                auto transaction{ session.createWriteTransaction() };
 
                 for (const TrackId trackId : tracksToRemove)
                 {
@@ -113,7 +113,7 @@ namespace Scanner
 
         LMS_LOG(DBUPDATER, DEBUG) << "Checking orphan clusters...";
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         // Now process orphan Cluster (no track)
         auto clusterIds{ Cluster::findOrphans(session) };
@@ -132,7 +132,7 @@ namespace Scanner
         LMS_LOG(DBUPDATER, DEBUG) << "Checking orphan artists...";
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto artistIds{ Artist::findOrphanIds(session) };
         for (const ArtistId artistId : artistIds.results)
@@ -151,7 +151,7 @@ namespace Scanner
 
         // TODO, by batch
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         auto releases{ Release::findOrphanIds(session) };
         for (const ReleaseId releaseId : releases.results)

src/libs/services/scanner/impl/ScanStepScanFiles.cpp

@@ -337,7 +337,7 @@ namespace Scanner
         {
             // Skip file if last write is the same
             Database::Session& dbSession{ _db.getTLSSession() };
-            auto transaction{ _db.getTLSSession().createSharedTransaction() };
+            auto transaction{ _db.getTLSSession().createReadTransaction() };
 
             const Track::pointer track{ Track::findByPath(dbSession, file) };
 
@@ -359,7 +359,7 @@ namespace Scanner
         stats.scans++;
 
         Database::Session& dbSession{ _db.getTLSSession() };
-        auto uniqueTransaction{ dbSession.createUniqueTransaction() };
+        auto transaction{ dbSession.createWriteTransaction() };
 
         Track::pointer track{ Track::findByPath(dbSession, file) };
 

src/libs/services/scanner/impl/ScannerService.cpp

@@ -345,7 +345,7 @@ namespace Scanner
 
         newSettings.skipDuplicateMBID = Service<IConfig>::get()->getBool("scanner-skip-duplicate-mbid", false);
         {
-            auto transaction{ _dbSession.createSharedTransaction() };
+            auto transaction{ _dbSession.createReadTransaction() };
 
             const ScanSettings::pointer scanSettings{ ScanSettings::get(_dbSession) };
 

src/libs/services/scrobbling/impl/ScrobblingService.cpp

@@ -77,7 +77,7 @@ namespace Scrobbling
         std::optional<ScrobblingBackend> backend;
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
         if (const User::pointer user{ User::find(session, userId) })
             backend = user->getScrobblingBackend();
 
@@ -93,7 +93,7 @@ namespace Scrobbling
             return res;
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         res = Database::Listen::getRecentArtists(session, userId, *backend, clusterIds, linkType, range);
         return res;
@@ -108,7 +108,7 @@ namespace Scrobbling
             return res;
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         res = Database::Listen::getRecentReleases(session, userId, *backend, clusterIds, range);
         return res;
@@ -123,7 +123,7 @@ namespace Scrobbling
             return res;
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         res = Database::Listen::getRecentTracks(session, userId, *backend, clusterIds, range);
         return res;
@@ -136,7 +136,7 @@ namespace Scrobbling
             return {};
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const Database::Listen::pointer listen{ Database::Listen::getMostRecentListen(session, userId, *backend, releaseId) };
         return listen ? listen->getDateTime() : Wt::WDateTime{};
@@ -149,7 +149,7 @@ namespace Scrobbling
             return {};
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const Database::Listen::pointer listen{ Database::Listen::getMostRecentListen(session, userId, *backend, trackId) };
         return listen ? listen->getDateTime() : Wt::WDateTime{};
@@ -165,7 +165,7 @@ namespace Scrobbling
             return res;
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         res = Database::Listen::getTopArtists(session, userId, *backend, clusterIds, linkType, range);
         return res;
@@ -180,7 +180,7 @@ namespace Scrobbling
             return res;
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         res = Database::Listen::getTopReleases(session, userId, *backend, clusterIds, range);
         return res;
@@ -195,7 +195,7 @@ namespace Scrobbling
             return res;
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         res = Database::Listen::getTopTracks(session, userId, *backend, clusterIds, range);
         return res;

src/libs/services/scrobbling/impl/internal/InternalBackend.cpp

@@ -48,7 +48,7 @@ namespace Scrobbling
     void InternalBackend::addTimedListen(const TimedListen& listen)
     {
         Database::Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         if (Database::Listen::find(session, listen.userId, listen.trackId, Database::ScrobblingBackend::Internal, listen.listenedAt))
             return;

src/libs/services/scrobbling/impl/listenbrainz/ListenBrainzBackend.cpp

@@ -36,7 +36,7 @@ namespace Scrobbling::ListenBrainz
     {
         bool canBeScrobbled(Session& session, TrackId trackId, std::chrono::seconds duration)
         {
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             const Track::pointer track{ Track::find(session, trackId) };
             if (!track)

src/libs/services/scrobbling/impl/listenbrainz/ListensSynchronizer.cpp

@@ -46,7 +46,7 @@ namespace
 
     std::optional<Wt::Json::Object> listenToJsonPayload(Database::Session& session, const Scrobbling::Listen& listen, const Wt::WDateTime& timePoint)
     {
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         const Database::Track::pointer track{ Database::Track::find(session, listen.trackId) };
         if (!track)
@@ -143,7 +143,7 @@ namespace
     {
         using namespace Database;
 
-        auto transaction{ session.createSharedTransaction() };
+        auto transaction{ session.createReadTransaction() };
 
         // first try to match using track MBID, and then fallback on possibly ambiguous info
         if (listen.trackMBID)
@@ -289,7 +289,7 @@ namespace Scrobbling::ListenBrainz
         using namespace Database;
 
         Session& session{ _db.getTLSSession() };
-        auto transaction{ session.createUniqueTransaction() }; // TODO: unique only if needed
+        auto transaction{ session.createWriteTransaction() }; // TODO: unique only if needed
 
         Database::Listen::pointer dbListen{ Database::Listen::find(session, listen.userId, listen.trackId, Database::ScrobblingBackend::ListenBrainz, listen.listenedAt) };
         if (!dbListen)
@@ -324,7 +324,7 @@ namespace Scrobbling::ListenBrainz
         {
             Database::Session& session{ _db.getTLSSession() };
 
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
 
             Database::Listen::FindParameters params;
             params.setScrobblingBackend(Database::ScrobblingBackend::ListenBrainz)
@@ -408,7 +408,7 @@ namespace Scrobbling::ListenBrainz
         Database::RangeResults<Database::UserId> userIds;
         {
             Database::Session& session{ _db.getTLSSession() };
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
             userIds = Database::User::find(_db.getTLSSession(), Database::User::FindParameters{}.setScrobblingBackend(Database::ScrobblingBackend::ListenBrainz));
         }
 

src/libs/services/scrobbling/impl/listenbrainz/Utils.cpp

@@ -30,7 +30,7 @@ namespace Scrobbling::ListenBrainz::Utils
 	std::optional<UUID>
 	getListenBrainzToken(Database::Session& session, Database::UserId userId)
 	{
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		const Database::User::pointer user {Database::User::find(session, userId)};
 		if (!user)

src/libs/subsonic/impl/SubsonicResource.cpp

@@ -135,7 +135,7 @@ namespace API::Subsonic
 
         void checkUserTypeIsAllowed(RequestContext& context, EnumSet<Database::UserType> allowedUserTypes)
         {
-            auto transaction{ context.dbSession.createSharedTransaction() };
+            auto transaction{ context.dbSession.createReadTransaction() };
 
             User::pointer currentUser{ User::find(context.dbSession, context.userId) };
             if (!currentUser)
@@ -403,7 +403,7 @@ namespace API::Subsonic
         if (request.continuation())
         {
             Database::Session& session{ _db.getTLSSession() };
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             const auto user{ Database::User::find(session, clientInfo.user) };
             if (!user)

src/libs/subsonic/impl/entrypoints/AlbumSongLists.cpp

@@ -56,7 +56,7 @@ namespace API::Subsonic
             Scrobbling::IScrobblingService& scrobblingService{ *Service<Scrobbling::IScrobblingService>::get() };
             Feedback::IFeedbackService& feedbackService{ *Service<Feedback::IFeedbackService>::get() };
 
-            auto transaction{ context.dbSession.createSharedTransaction() };
+            auto transaction{ context.dbSession.createReadTransaction() };
 
             User::pointer user{ User::find(context.dbSession, context.userId) };
             if (!user)
@@ -156,7 +156,7 @@ namespace API::Subsonic
 
         Response handleGetStarredRequestCommon(RequestContext& context, bool id3)
         {
-            auto transaction{ context.dbSession.createSharedTransaction() };
+            auto transaction{ context.dbSession.createReadTransaction() };
 
             User::pointer user{ User::find(context.dbSession, context.userId) };
             if (!user)
@@ -214,7 +214,7 @@ namespace API::Subsonic
         if (size > defaultMaxCountSize)
             throw ParameterValueTooHighGenericError{ "size", defaultMaxCountSize };
 
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         User::pointer user{ User::find(context.dbSession, context.userId) };
         if (!user)
@@ -247,7 +247,7 @@ namespace API::Subsonic
 
         std::size_t offset{ getParameterAs<std::size_t>(context.parameters, "offset").value_or(0) };
 
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         auto clusterType{ ClusterType::find(context.dbSession, "GENRE") };
         if (!clusterType)

src/libs/subsonic/impl/entrypoints/Bookmarks.cpp

@@ -34,7 +34,7 @@ namespace API::Subsonic
 
     Response handleGetBookmarks(RequestContext& context)
     {
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         User::pointer user{ User::find(context.dbSession, context.userId) };
         if (!user)
@@ -64,7 +64,7 @@ namespace API::Subsonic
         unsigned long position{ getMandatoryParameterAs<unsigned long>(context.parameters, "position") };
         const std::optional<std::string> comment{ getParameterAs<std::string>(context.parameters, "comment") };
 
-        auto transaction{ context.dbSession.createUniqueTransaction() };
+        auto transaction{ context.dbSession.createWriteTransaction() };
 
         const User::pointer user{ User::find(context.dbSession, context.userId) };
         if (!user)
@@ -91,7 +91,7 @@ namespace API::Subsonic
         // Mandatory params
         TrackId trackId{ getMandatoryParameterAs<TrackId>(context.parameters, "id") };
 
-        auto transaction{ context.dbSession.createUniqueTransaction() };
+        auto transaction{ context.dbSession.createWriteTransaction() };
 
         auto bookmark{ TrackBookmark::find(context.dbSession, context.userId, trackId) };
         if (!bookmark)

src/libs/subsonic/impl/entrypoints/Browsing.cpp

@@ -58,7 +58,7 @@ namespace API::Subsonic
             Response::Node& artistInfoNode{ response.createNode(id3 ? Response::Node::Key{ "artistInfo2" } : Response::Node::Key{ "artistInfo" }) };
 
             {
-                auto transaction{ context.dbSession.createSharedTransaction() };
+                auto transaction{ context.dbSession.createReadTransaction() };
 
                 const Artist::pointer artist{ Artist::find(context.dbSession, id) };
                 if (!artist)
@@ -72,7 +72,7 @@ namespace API::Subsonic
             auto similarArtistsId{ Service<Recommendation::IRecommendationService>::get()->getSimilarArtists(id, {TrackArtistLinkType::Artist, TrackArtistLinkType::ReleaseArtist}, count) };
 
             {
-                auto transaction{ context.dbSession.createSharedTransaction() };
+                auto transaction{ context.dbSession.createReadTransaction() };
 
                 User::pointer user{ User::find(context.dbSession, context.userId) };
                 if (!user)
@@ -99,7 +99,7 @@ namespace API::Subsonic
 
             Artist::FindParameters parameters;
             {
-                auto transaction{ context.dbSession.createSharedTransaction() };
+                auto transaction{ context.dbSession.createReadTransaction() };
 
                 User::pointer user{ User::find(context.dbSession, context.userId) };
                 if (!user)
@@ -129,7 +129,7 @@ namespace API::Subsonic
             bool hasMoreArtists{ true };
             while (hasMoreArtists)
             {
-                auto transaction{ context.dbSession.createSharedTransaction() };
+                auto transaction{ context.dbSession.createReadTransaction() };
 
                 parameters.setRange(Range{ currentArtistOffset, batchSize });
                 const auto artists{ Artist::find(context.dbSession, parameters) };
@@ -159,7 +159,7 @@ namespace API::Subsonic
 
                 for (const ArtistId artistId : artistIds)
                 {
-                    auto transaction{ context.dbSession.createSharedTransaction() };
+                    auto transaction{ context.dbSession.createReadTransaction() };
                     User::pointer user{ User::find(context.dbSession, context.userId) };
                     if (!user)
                         throw UserNotAuthorizedError{};
@@ -181,7 +181,7 @@ namespace API::Subsonic
 
             const std::size_t meanTrackCountPerArtist{ (count / artistIds.size()) + 1 };
 
-            auto transaction{ context.dbSession.createSharedTransaction() };
+            auto transaction{ context.dbSession.createReadTransaction() };
 
             std::vector<TrackId> tracks;
             tracks.reserve(count);
@@ -212,7 +212,7 @@ namespace API::Subsonic
 
             const std::size_t meanTrackCountPerRelease{ (count / releaseIds.size()) + 1 };
 
-            auto transaction{ context.dbSession.createSharedTransaction() };
+            auto transaction{ context.dbSession.createReadTransaction() };
 
             std::vector<TrackId> tracks;
             tracks.reserve(count);
@@ -258,7 +258,7 @@ namespace API::Subsonic
 
             Random::shuffleContainer(tracks);
 
-            auto transaction{ context.dbSession.createSharedTransaction() };
+            auto transaction{ context.dbSession.createReadTransaction() };
 
             User::pointer user{ User::find(context.dbSession, context.userId) };
             if (!user)
@@ -307,7 +307,7 @@ namespace API::Subsonic
         Response response{ Response::createOkResponse(context.serverProtocolVersion) };
         Response::Node& directoryNode{ response.createNode("directory") };
 
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         User::pointer user{ User::find(context.dbSession, context.userId) };
         if (!user)
@@ -366,7 +366,7 @@ namespace API::Subsonic
 
         Response::Node& genresNode{ response.createNode("genres") };
 
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         const ClusterType::pointer clusterType{ ClusterType::find(context.dbSession, "GENRE") };
         if (clusterType)
@@ -390,7 +390,7 @@ namespace API::Subsonic
         // Mandatory params
         ArtistId id{ getMandatoryParameterAs<ArtistId>(context.parameters, "id") };
 
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         const Artist::pointer artist{ Artist::find(context.dbSession, id) };
         if (!artist)
@@ -417,7 +417,7 @@ namespace API::Subsonic
         // Mandatory params
         ReleaseId id{ getMandatoryParameterAs<ReleaseId>(context.parameters, "id") };
 
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         Release::pointer release{ Release::find(context.dbSession, id) };
         if (!release)
@@ -444,7 +444,7 @@ namespace API::Subsonic
         // Mandatory params
         TrackId id{ getMandatoryParameterAs<TrackId>(context.parameters, "id") };
 
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         const Track::pointer track{ Track::find(context.dbSession, id) };
         if (!track)

src/libs/subsonic/impl/entrypoints/MediaRetrieval.cpp

@@ -127,7 +127,7 @@ namespace API::Subsonic
 
             StreamParameters parameters;
 
-            auto transaction{ context.dbSession.createSharedTransaction() };
+            auto transaction{ context.dbSession.createReadTransaction() };
 
             const User::pointer user{ User::find(context.dbSession, context.userId) };
             if (!user)
@@ -199,7 +199,7 @@ namespace API::Subsonic
 
             std::filesystem::path trackPath;
             {
-                auto transaction{ context.dbSession.createSharedTransaction() };
+                auto transaction{ context.dbSession.createReadTransaction() };
 
                 auto track{ Track::find(context.dbSession, id) };
                 if (!track)

src/libs/subsonic/impl/entrypoints/Playlists.cpp

@@ -34,7 +34,7 @@ namespace API::Subsonic
 
     Response handleGetPlaylistsRequest(RequestContext& context)
     {
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         Response response{ Response::createOkResponse(context.serverProtocolVersion) };
         Response::Node& playlistsNode{ response.createNode("playlists") };
@@ -58,7 +58,7 @@ namespace API::Subsonic
         // Mandatory params
         TrackListId trackListId{ getMandatoryParameterAs<TrackListId>(context.parameters, "id") };
 
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         User::pointer user{ User::find(context.dbSession, context.userId) };
         if (!user)
@@ -91,7 +91,7 @@ namespace API::Subsonic
         if (!name && !id)
             throw RequiredParameterMissingError{ "name or id" };
 
-        auto transaction{ context.dbSession.createUniqueTransaction() };
+        auto transaction{ context.dbSession.createWriteTransaction() };
 
         User::pointer user{ User::find(context.dbSession, context.userId) };
         if (!user)
@@ -140,7 +140,7 @@ namespace API::Subsonic
         std::vector<TrackId> trackIdsToAdd{ getMultiParametersAs<TrackId>(context.parameters, "songIdToAdd") };
         std::vector<std::size_t> trackPositionsToRemove{ getMultiParametersAs<std::size_t>(context.parameters, "songIndexToRemove") };
 
-        auto transaction{ context.dbSession.createUniqueTransaction() };
+        auto transaction{ context.dbSession.createWriteTransaction() };
 
         User::pointer user{ User::find(context.dbSession, context.userId) };
         if (!user)
@@ -189,7 +189,7 @@ namespace API::Subsonic
     {
         TrackListId id{ getMandatoryParameterAs<TrackListId>(context.parameters, "id") };
 
-        auto transaction{ context.dbSession.createUniqueTransaction() };
+        auto transaction{ context.dbSession.createWriteTransaction() };
 
         User::pointer user{ User::find(context.dbSession, context.userId) };
         if (!user)

src/libs/subsonic/impl/entrypoints/Searching.cpp

@@ -67,7 +67,7 @@ namespace API::Subsonic
             Response response{ Response::createOkResponse(context.serverProtocolVersion) };
             Response::Node& searchResult2Node{ response.createNode(id3 ? "searchResult3" : "searchResult2") };
 
-            auto transaction{ context.dbSession.createSharedTransaction() };
+            auto transaction{ context.dbSession.createReadTransaction() };
 
             User::pointer user{ User::find(context.dbSession, context.userId) };
             if (!user)

src/libs/subsonic/impl/entrypoints/UserManagement.cpp

@@ -28,7 +28,7 @@ namespace API::Subsonic
     {
         std::string username{ getMandatoryParameterAs<std::string>(context.parameters, "username") };
 
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         checkUserIsMySelfOrAdmin(context, username);
 
@@ -44,7 +44,7 @@ namespace API::Subsonic
 
     Response handleGetUsersRequest(RequestContext& context)
     {
-        auto transaction{ context.dbSession.createSharedTransaction() };
+        auto transaction{ context.dbSession.createReadTransaction() };
 
         Response response{ Response::createOkResponse(context.serverProtocolVersion) };
         Response::Node& usersNode{ response.createNode("users") };
@@ -67,7 +67,7 @@ namespace API::Subsonic
 
         Database::UserId userId;
         {
-            auto transaction{ context.dbSession.createUniqueTransaction() };
+            auto transaction{ context.dbSession.createWriteTransaction() };
 
             User::pointer user{ User::find(context.dbSession, username) };
             if (user)
@@ -79,7 +79,7 @@ namespace API::Subsonic
 
         auto removeCreatedUser{ [&]()
         {
-            auto transaction {context.dbSession.createUniqueTransaction()};
+            auto transaction {context.dbSession.createWriteTransaction()};
             User::pointer user {User::find(context.dbSession, userId)};
             if (user)
                 user.remove();
@@ -112,7 +112,7 @@ namespace API::Subsonic
     {
         std::string username{ getMandatoryParameterAs<std::string>(context.parameters, "username") };
 
-        auto transaction{ context.dbSession.createUniqueTransaction() };
+        auto transaction{ context.dbSession.createWriteTransaction() };
 
         User::pointer user{ User::find(context.dbSession, username) };
         if (!user)
@@ -134,7 +134,7 @@ namespace API::Subsonic
 
         UserId userId;
         {
-            auto transaction{ context.dbSession.createSharedTransaction() };
+            auto transaction{ context.dbSession.createReadTransaction() };
 
             User::pointer user{ User::find(context.dbSession, username) };
             if (!user)
@@ -177,7 +177,7 @@ namespace API::Subsonic
         {
             Database::UserId userId;
             {
-                auto transaction{ context.dbSession.createSharedTransaction() };
+                auto transaction{ context.dbSession.createReadTransaction() };
 
                 checkUserIsMySelfOrAdmin(context, username);
 

src/lms/main.cpp

@@ -234,8 +234,8 @@ int main(int argc, char* argv[])
 
         IOContextRunner ioContextRunner{ ioContext, getThreadCount() };
 
-        // Initializing a connection pool to the database that will be shared along services
+        // Connection pool size must be twice the number of threads: we have at least 2 io pools with getThreadCount() each and they all may access the database
-        Database::Db database{ config->getPath("working-dir") / "lms.db", getThreadCount() };
+        Database::Db database{ config->getPath("working-dir") / "lms.db", getThreadCount() * 2 };
         {
             Database::Session session{ database };
             session.prepareTables();

src/lms/ui/Auth.cpp

@@ -106,7 +106,7 @@ class AuthModel : public Wt::WFormModel
 		{
 			bool isDemo;
 			{
-				auto transaction {LmsApp->getDbSession().createUniqueTransaction()};
+				auto transaction {LmsApp->getDbSession().createWriteTransaction()};
 
 				Database::User::pointer user {Database::User::find(LmsApp->getDbSession(), valueText(LoginNameField).toUTF8())};
 				user.modify()->setLastLogin(Wt::WDateTime::currentDateTime());
@@ -200,7 +200,7 @@ Auth::Auth()
 	setFormWidget(AuthModel::RememberMeField, std::make_unique<Wt::WCheckBox>());
 
 	{
-		auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+		auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 		Database::User::pointer demoUser {Database::User::findDemoUser(LmsApp->getDbSession())};
 		if (demoUser)

src/lms/ui/LmsApplication.cpp

@@ -169,7 +169,7 @@ LmsApplication::isUserAuthStrong() const
 Database::UserType
 LmsApplication::getUserType()
 {
-	auto transaction {getDbSession().createSharedTransaction()};
+	auto transaction {getDbSession().createReadTransaction()};
 
 	return getUser()->getType();
 }
@@ -177,7 +177,7 @@ LmsApplication::getUserType()
 std::string
 LmsApplication::getUserLoginName()
 {
-	auto transaction {getDbSession().createSharedTransaction()};
+	auto transaction {getDbSession().createReadTransaction()};
 
 	return getUser()->getLoginName();
 }
@@ -246,7 +246,7 @@ LmsApplication::processPasswordAuth()
 	// If here is no account in the database, launch the first connection wizard
 	bool firstConnection {};
 	{
-		auto transaction {getDbSession().createSharedTransaction()};
+		auto transaction {getDbSession().createReadTransaction()};
 		firstConnection = Database::User::getCount(getDbSession()) == 0;
 	}
 
@@ -360,7 +360,7 @@ void
 LmsApplication::logoutUser()
 {
 	{
-		auto transaction {getDbSession().createUniqueTransaction()};
+		auto transaction {getDbSession().createWriteTransaction()};
 		getUser().modify()->clearAuthTokens();
 	}
 

src/lms/ui/MediaPlayer.cpp

@@ -237,7 +237,7 @@ namespace UserInterface
 
         std::ostringstream oss;
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
             const auto track{ Database::Track::find(LmsApp->getDbSession(), trackId) };
             if (!track)

src/lms/ui/PlayQueue.cpp

@@ -95,7 +95,7 @@ namespace UserInterface
 
                 auto model{ std::make_shared<TrackListModel>() };
 
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
                 TrackList::FindParameters params;
                 params.setType(TrackListType::Playlist);
@@ -148,7 +148,7 @@ namespace UserInterface
         shuffleBtn->clicked().connect([=]
             {
                 {
-                    auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+                    auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                     Database::TrackList::pointer queue{ getQueue() };
                     auto entries{ queue->getEntries() };
@@ -165,13 +165,13 @@ namespace UserInterface
         _repeatBtn = bindNew<Wt::WCheckBox>("repeat-btn");
         _repeatBtn->clicked().connect([=]
             {
-                auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+                auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                 if (!LmsApp->getUser()->isDemo())
                     LmsApp->getUser().modify()->setRepeatAll(isRepeatAllSet());
             });
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
             if (LmsApp->getUser()->isRepeatAllSet())
                 _repeatBtn->setCheckState(Wt::CheckState::Checked);
         }
@@ -180,7 +180,7 @@ namespace UserInterface
         _radioBtn->clicked().connect([=]
             {
                 {
-                    auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+                    auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                     if (!LmsApp->getUser()->isDemo())
                         LmsApp->getUser().modify()->setRadio(isRadioModeSet());
@@ -191,7 +191,7 @@ namespace UserInterface
 
         bool isRadioModeSet{};
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
             isRadioModeSet = LmsApp->getUser()->isRadioSet();
         }
         if (isRadioModeSet)
@@ -213,7 +213,7 @@ namespace UserInterface
                 std::size_t trackPos{};
 
                 {
-                    auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                    auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                     trackPos = LmsApp->getUser()->getCurPlayingTrackPos();
                 }
 
@@ -222,7 +222,7 @@ namespace UserInterface
 
         LmsApp->preQuit().connect([=]
             {
-                auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+                auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                 if (LmsApp->getUser()->isDemo())
                 {
@@ -252,14 +252,14 @@ namespace UserInterface
 
     bool PlayQueue::isFull() const
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
         return getQueue()->getCount() == getCapacity();
     }
 
     void PlayQueue::clearTracks()
     {
         {
-            auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+            auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
             getQueue().modify()->clear();
         }
 
@@ -283,7 +283,7 @@ namespace UserInterface
         Database::TrackId trackId{};
         std::optional<float> replayGain{};
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
             const Database::TrackList::pointer queue{ getQueue() };
 
@@ -345,13 +345,13 @@ namespace UserInterface
 
     std::size_t PlayQueue::getCount()
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
         return getQueue()->getCount();
     }
 
     void PlayQueue::initTrackLists()
     {
-        auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+        auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
         Database::TrackList::pointer queue;
         Database::TrackList::pointer radioStartingTracks;
@@ -374,7 +374,7 @@ namespace UserInterface
 
     void PlayQueue::updateInfo()
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Database::TrackList::pointer queue{ getQueue() };
         const std::size_t trackCount{ queue->getCount() };
@@ -398,7 +398,7 @@ namespace UserInterface
     void PlayQueue::enqueueTracks(const std::vector<Database::TrackId>& trackIds)
     {
         {
-            auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+            auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
             Database::TrackList::pointer queue{ getQueue() };
             const std::size_t queueSize{ queue->getCount() };
@@ -427,7 +427,7 @@ namespace UserInterface
     {
         std::vector<Database::TrackId> tracks;
 
-        auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+        auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
         Database::TrackList::pointer queue{ getQueue() };
         std::vector<Database::TrackListEntry::pointer> entries{ queue->getEntries(Database::Range {_trackPos ? *_trackPos + 1 : 0, getCapacity()}) };
@@ -489,7 +489,7 @@ namespace UserInterface
 
     void PlayQueue::addSome()
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Database::TrackList::pointer queue{ getQueue() };
         const auto tracklistEntries{ queue->getEntries(Database::Range {_entriesContainer->getCount(), _batchSize}) };
@@ -550,7 +550,7 @@ namespace UserInterface
             {
                 // Remove the entry n both the widget tree and the playqueue
                 {
-                    auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+                    auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                     Database::TrackListEntry::pointer entryToRemove{ Database::TrackListEntry::getById(LmsApp->getDbSession(), tracklistEntryId) };
                     entryToRemove.remove();
@@ -584,7 +584,7 @@ namespace UserInterface
         Wt::WPushButton* starBtn{ entry->bindNew<Wt::WPushButton>("star", Wt::WString::tr(isStarred() ? "Lms.Explore.unstar" : "Lms.Explore.star")) };
         starBtn->clicked().connect([=]
             {
-                auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+                auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                 if (isStarred())
                 {
@@ -609,7 +609,7 @@ namespace UserInterface
 
         bool addTracks{};
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
             const Database::TrackList::pointer queue{ getQueue() };
 
@@ -776,7 +776,7 @@ namespace UserInterface
 
         {
             Session& session{ LmsApp->getDbSession() };
-            auto transaction{ session.createUniqueTransaction() };
+            auto transaction{ session.createWriteTransaction() };
             TrackList::pointer trackList{ session.create<TrackList>(name.toUTF8(), TrackListType::Playlist, false, LmsApp->getUser()) };
             trackListId = trackList->getId();
         }
@@ -789,7 +789,7 @@ namespace UserInterface
         using namespace Database;
 
         Session& session{ LmsApp->getDbSession() };
-        auto transaction{ session.createUniqueTransaction() };
+        auto transaction{ session.createWriteTransaction() };
 
         TrackList::pointer trackList{ TrackList::find(LmsApp->getDbSession(), trackListId) };
         trackList.modify()->clear();

src/lms/ui/SettingsView.cpp

@@ -134,7 +134,7 @@ namespace UserInterface
 
         void saveData()
         {
-            auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+            auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
             User::pointer user{ LmsApp->getUser() };
 
@@ -202,7 +202,7 @@ namespace UserInterface
 
         void loadData()
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
             User::pointer user{ LmsApp->getUser() };
 
@@ -560,7 +560,7 @@ namespace UserInterface
         saveBtn->clicked().connect([=]
             {
                 {
-                    auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                    auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
                     if (LmsApp->getUser()->isDemo())
                     {

src/lms/ui/Utils.cpp

@@ -83,7 +83,7 @@ namespace UserInterface::Utils
 
     std::unique_ptr<Wt::WInteractWidget> createCluster(Database::ClusterId clusterId, bool canDelete)
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Database::Cluster::pointer cluster{ Database::Cluster::find(LmsApp->getDbSession(), clusterId) };
         if (!cluster)
@@ -124,7 +124,7 @@ namespace UserInterface::Utils
 
         bool firstArtist{ true };
 
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
         for (const ArtistId artistId : artistIds)
         {
             const Artist::pointer artist{ Artist::find(LmsApp->getDbSession(), artistId) };
@@ -152,7 +152,7 @@ namespace UserInterface::Utils
         std::string_view::size_type currentOffset{};
 
         auto result{ std::make_unique<Wt::WContainerWidget>() };
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         // consider order is guaranteed + we will likely succeed
         for (const ArtistId artistId : artistIds)

src/lms/ui/admin/DatabaseSettingsView.cpp

@@ -85,7 +85,7 @@ class DatabaseSettingsModel : public Wt::WFormModel
 
 		void loadData()
 		{
-			auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+			auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 			const ScanSettings::pointer scanSettings {ScanSettings::get(LmsApp->getDbSession())};
 
@@ -120,7 +120,7 @@ class DatabaseSettingsModel : public Wt::WFormModel
 
 		void saveData()
 		{
-			auto transaction {LmsApp->getDbSession().createUniqueTransaction()};
+			auto transaction {LmsApp->getDbSession().createWriteTransaction()};
 
 			ScanSettings::pointer scanSettings {ScanSettings::get(LmsApp->getDbSession())};
 

src/lms/ui/admin/InitWizardView.cpp

@@ -60,7 +60,7 @@ class InitWizardModel : public Wt::WFormModel
 
 		void saveData()
 		{
-			auto transaction(LmsApp->getDbSession().createUniqueTransaction());
+			auto transaction(LmsApp->getDbSession().createWriteTransaction());
 
 			// Check if a user already exist
 			// If it's the case, just do nothing

src/lms/ui/admin/ScannerController.cpp

@@ -93,7 +93,7 @@ class ReportResource : public Wt::WResource
 			response.out() << Wt::WString::tr("Lms.Admin.ScannerController.duplicates-header").arg(_stats->duplicates.size()).toUTF8() << std::endl;
 
 			{
-				auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+				auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 				for (const auto& duplicate : _stats->duplicates)
 				{

src/lms/ui/admin/UserView.cpp

@@ -76,7 +76,7 @@ class UserModel : public Wt::WFormModel
 
 		void saveData()
 		{
-			auto transaction {LmsApp->getDbSession().createUniqueTransaction()};
+			auto transaction {LmsApp->getDbSession().createWriteTransaction()};
 
 			if (_userId)
 			{
@@ -112,7 +112,7 @@ class UserModel : public Wt::WFormModel
 			if (!_userId)
 				return;
 
-			auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+			auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 			const User::pointer user {User::find(LmsApp->getDbSession(), *_userId)};
 			if (!user)
@@ -125,7 +125,7 @@ class UserModel : public Wt::WFormModel
 		{
 			if (_userId)
 			{
-				auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+				auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 				const User::pointer user {User::find(LmsApp->getDbSession(), *_userId)};
 				return user->getType();
@@ -138,7 +138,7 @@ class UserModel : public Wt::WFormModel
 		{
 			if (_userId)
 			{
-				auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+				auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 				const User::pointer user {User::find(LmsApp->getDbSession(), *_userId)};
 				return user->getLoginName();
@@ -153,7 +153,7 @@ class UserModel : public Wt::WFormModel
 
 			if (field == LoginField)
 			{
-				auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+				auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 				const User::pointer user {User::find(LmsApp->getDbSession(), valueText(LoginField).toUTF8())};
 				if (user)
@@ -161,7 +161,7 @@ class UserModel : public Wt::WFormModel
 			}
 			else if (field == DemoField)
 			{
-				auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+				auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 				if (Wt::asNumber(value(DemoField)) && User::findDemoUser(LmsApp->getDbSession()))
 					error = Wt::WString::tr("Lms.Admin.User.demo-account-already-exists");
@@ -209,7 +209,7 @@ UserView::refreshView()
 
 	if (userId)
 	{
-		auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+		auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 		const User::pointer user {User::find(LmsApp->getDbSession(), *userId)};
 		if (!user)

src/lms/ui/admin/UsersView.cpp

@@ -70,7 +70,7 @@ UsersView::refreshView()
 
 	_container->clear();
 
-	auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+	auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 	const User::IdType currentUserId {LmsApp->getUser()};
 	for (const UserId userId : User::find(LmsApp->getDbSession(), User::FindParameters {}).results)
@@ -112,7 +112,7 @@ UsersView::refreshView()
 			delBtn->clicked().connect([=]
 			{
 				{
-					auto transaction {LmsApp->getDbSession().createUniqueTransaction()};
+					auto transaction {LmsApp->getDbSession().createWriteTransaction()};
 
 					User::pointer user {User::find(LmsApp->getDbSession(), userId)};
 					if (user)

src/lms/ui/explore/ArtistCollector.cpp

@@ -77,7 +77,7 @@ namespace UserInterface
             params.setRange(range);
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 artists = Artist::findIds(LmsApp->getDbSession(), params);
             }
             break;
@@ -92,7 +92,7 @@ namespace UserInterface
             params.setRange(range);
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 artists = Artist::findIds(LmsApp->getDbSession(), params);
             }
             break;
@@ -107,7 +107,7 @@ namespace UserInterface
             params.setRange(range);
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 artists = Artist::findIds(LmsApp->getDbSession(), params);
             }
             break;
@@ -133,7 +133,7 @@ namespace UserInterface
             params.setRange(Range{ 0, getMaxCount() });
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 _randomArtists = Artist::findIds(LmsApp->getDbSession(), params);
             }
         }

src/lms/ui/explore/ArtistListHelpers.cpp

@@ -47,7 +47,7 @@ namespace UserInterface::ArtistListHelpers
 
 		EnumSet<TrackArtistLinkType> usedLinkTypes;
 		{
-			auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+			auto transaction {LmsApp->getDbSession().createReadTransaction()};
 			usedLinkTypes = TrackArtistLink::findUsedTypes(LmsApp->getDbSession());
 		}
 

src/lms/ui/explore/ArtistView.cpp

@@ -57,7 +57,7 @@ namespace UserInterface
                 const auto mbid{ UUID::fromString(wApp->internalPathNextPart("/artist/mbid/")) };
                 if (mbid)
                 {
-                    auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                    auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                     if (const Database::Artist::pointer artist{ Database::Artist::find(LmsApp->getDbSession(), *mbid) })
                         return artist->getId();
                 }
@@ -124,7 +124,7 @@ namespace UserInterface
 
         const auto similarArtistIds{ Service<Recommendation::IRecommendationService>::get()->getSimilarArtists(*artistId, {TrackArtistLinkType::Artist, TrackArtistLinkType::ReleaseArtist}, 5) };
 
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Database::Artist::pointer artist{ Database::Artist::find(LmsApp->getDbSession(), *artistId) };
         if (!artist)
@@ -334,7 +334,7 @@ namespace UserInterface
 
     void Artist::addSomeReleases(ReleaseContainer& releaseContainer)
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         if (const Database::Artist::pointer artist{ Database::Artist::find(LmsApp->getDbSession(), _artistId) })
         {
@@ -349,7 +349,7 @@ namespace UserInterface
     bool Artist::addSomeNonReleaseTracks()
     {
         bool areTracksAdded{};
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Range range{ static_cast<std::size_t>(_trackContainer->getCount()), _tracksBatchSize };
 

src/lms/ui/explore/ArtistsView.cpp

@@ -121,7 +121,7 @@ Artists::addSome()
 	const auto artistIds {_artistCollector.get(Range {static_cast<std::size_t>(_container->getCount()), _batchSize})};
 
 	{
-		auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+		auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 		for (const ArtistId artistId : artistIds.results)
 		{

src/lms/ui/explore/Filters.cpp

@@ -56,7 +56,7 @@ Filters::showDialog()
 		ClusterId clusterId {};
 
 		{
-			auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+			auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 			ClusterType::pointer clusterType {ClusterType::find(LmsApp->getDbSession(), type)};
 			if (!clusterType)
@@ -82,7 +82,7 @@ Filters::showDialog()
 
 	// Populate data
 	{
-		auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+		auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 		const auto clusterTypesIds {ClusterType::findUsed(LmsApp->getDbSession())};
 		for (const ClusterTypeId clusterTypeId : clusterTypesIds.results)
@@ -109,7 +109,7 @@ Filters::showDialog()
 
 		valueCombo->clear();
 
-		auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+		auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 		auto clusterType {ClusterType::find(LmsApp->getDbSession(), name)};
 		for (const Cluster::pointer& cluster : clusterType->getClusters())

src/lms/ui/explore/PlayQueueController.cpp

@@ -37,7 +37,7 @@ namespace UserInterface
 
             std::vector<Database::TrackId> res;
 
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             for (const Database::ArtistId artistId : artistsId)
             {
@@ -66,7 +66,7 @@ namespace UserInterface
 
             std::vector<TrackId> res;
 
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             for (const ReleaseId releaseId : releasesId)
             {
@@ -93,7 +93,7 @@ namespace UserInterface
             using namespace Database;
             assert(maxTrackCount);
 
-            auto transaction{ session.createSharedTransaction() };
+            auto transaction{ session.createReadTransaction() };
 
             Database::Track::FindParameters params;
             params.setTrackList(trackListId);
@@ -154,7 +154,7 @@ namespace UserInterface
     {
         Database::ReleaseId releaseId;
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
             const Database::Track::pointer track{ Database::Track::find(LmsApp->getDbSession(), trackId) };
             if (!track || !track->getRelease())
                 return;

src/lms/ui/explore/ReleaseCollector.cpp

@@ -73,7 +73,7 @@ namespace UserInterface
             params.setRange(range);
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 releases = Release::findIds(LmsApp->getDbSession(), params);
             }
             break;
@@ -87,7 +87,7 @@ namespace UserInterface
             params.setRange(range);
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 releases = Release::findIds(LmsApp->getDbSession(), params);
             }
             break;
@@ -101,7 +101,7 @@ namespace UserInterface
             params.setRange(range);
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 releases = Release::findIds(LmsApp->getDbSession(), params);
             }
             break;
@@ -126,7 +126,7 @@ namespace UserInterface
             params.setRange(Range{ 0, getMaxCount() });
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 _randomReleases = Release::findIds(LmsApp->getDbSession(), params);
             }
         }

src/lms/ui/explore/ReleaseView.cpp

@@ -56,7 +56,7 @@ namespace UserInterface
     {
         void showReleaseInfoModal(Database::ReleaseId releaseId)
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
             const Database::Release::pointer release{ Database::Release::find(LmsApp->getDbSession(), releaseId) };
             if (!release)
@@ -174,7 +174,7 @@ namespace UserInterface
                 const auto mbid{ UUID::fromString(wApp->internalPathNextPart("/release/mbid/")) };
                 if (mbid)
                 {
-                    auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                    auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                     if (const Database::Release::pointer release{ Database::Release::find(LmsApp->getDbSession(), *mbid) })
                         return release->getId();
                 }
@@ -228,7 +228,7 @@ namespace UserInterface
 
         auto similarReleasesIds{ Service<Recommendation::IRecommendationService>::get()->getSimilarReleases(*releaseId, 6) };
 
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Database::Release::pointer release{ Database::Release::find(LmsApp->getDbSession(), *releaseId) };
         if (!release)
@@ -433,7 +433,7 @@ namespace UserInterface
                     Wt::WPushButton* starBtn{ entry->bindNew<Wt::WPushButton>("star", Wt::WString::tr(isStarred() ? "Lms.Explore.unstar" : "Lms.Explore.star")) };
                     starBtn->clicked().connect([=]
                         {
-                            auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+                            auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                             if (isStarred())
                             {

src/lms/ui/explore/ReleasesView.cpp

@@ -122,7 +122,7 @@ namespace UserInterface
         const auto releaseIds{ _releaseCollector.get(Range {static_cast<std::size_t>(_container->getCount()), _batchSize}) };
 
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
             for (const ReleaseId releaseId : releaseIds.results)
             {

src/lms/ui/explore/SearchView.cpp

@@ -150,7 +150,7 @@ namespace UserInterface
         const Range range{ _artists->getCount(), getBatchSize(Mode::Artist) };
         const RangeResults<ArtistId> artistIds{ _artistCollector.get(range) };
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
             for (const ArtistId artistId : artistIds.results)
             {
@@ -168,7 +168,7 @@ namespace UserInterface
         const Range range{ _releases->getCount(), getBatchSize(Mode::Release) };
         const RangeResults<ReleaseId> releaseIds{ _releaseCollector.get(range) };
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
             for (const ReleaseId releaseId : releaseIds.results)
             {
@@ -187,7 +187,7 @@ namespace UserInterface
         const RangeResults<TrackId> trackIds{ _trackCollector.get(range) };
 
         {
-            auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+            auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
             for (const TrackId trackId : trackIds.results)
             {

src/lms/ui/explore/TrackCollector.cpp

@@ -76,7 +76,7 @@ namespace UserInterface
             params.setRange(range);
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 tracks = Track::findIds(LmsApp->getDbSession(), params);
             }
             break;
@@ -90,7 +90,7 @@ namespace UserInterface
             params.setRange(range);
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 tracks = Track::findIds(LmsApp->getDbSession(), params);
             }
             break;
@@ -103,7 +103,7 @@ namespace UserInterface
             params.setRange(range);
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 tracks = Track::findIds(LmsApp->getDbSession(), params);
             }
             break;
@@ -128,7 +128,7 @@ namespace UserInterface
             params.setRange(Range{ 0, getMaxCount() });
 
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
                 _randomTracks = Track::findIds(LmsApp->getDbSession(), params);
             }
         }

src/lms/ui/explore/TrackListHelpers.cpp

@@ -49,7 +49,7 @@ namespace UserInterface::TrackListHelpers
 
     void showTrackInfoModal(Database::TrackId trackId, Filters& filters)
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Database::Track::pointer track{ Track::find(LmsApp->getDbSession(), trackId) };
         if (!track)
@@ -219,7 +219,7 @@ namespace UserInterface::TrackListHelpers
             Wt::WPushButton* starBtn{ entry->bindNew<Wt::WPushButton>("star", Wt::WString::tr(isStarred() ? "Lms.Explore.unstar" : "Lms.Explore.star")) };
             starBtn->clicked().connect([=]
                 {
-                    auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+                    auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                     if (isStarred())
                     {

src/lms/ui/explore/TrackListView.cpp

@@ -81,7 +81,7 @@ namespace UserInterface
         if (!trackListId)
             throw TrackListNotFoundException{};
 
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Database::TrackList::pointer trackList{ Database::TrackList::find(LmsApp->getDbSession(), *trackListId) };
         if (!trackList)
@@ -148,7 +148,7 @@ namespace UserInterface
                     delBtn->clicked().connect([=]
                         {
                             {
-                                auto transaction{ LmsApp->getDbSession().createUniqueTransaction() };
+                                auto transaction{ LmsApp->getDbSession().createWriteTransaction() };
 
                                 Database::TrackList::pointer trackList{ Database::TrackList::find(LmsApp->getDbSession(), *trackListId) };
                                 if (trackList)
@@ -180,7 +180,7 @@ namespace UserInterface
 
     void TrackList::addSome()
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         Database::Track::FindParameters params;
         params.setClusters(_filters.getClusterIds());

src/lms/ui/explore/TrackListsView.cpp

@@ -101,7 +101,7 @@ namespace UserInterface
 		const Range range {static_cast<std::size_t>(_container->getCount()), _batchSize};
 
 		Session& session {LmsApp->getDbSession()};
-		auto transaction {session.createSharedTransaction()};
+		auto transaction {session.createReadTransaction()};
 
 		TrackList::FindParameters params;
 		params.setClusters(_filters.getClusterIds());

src/lms/ui/explore/TracksView.cpp

@@ -119,7 +119,7 @@ namespace UserInterface
 
     void Tracks::addSome()
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const auto trackIds{ _trackCollector.get(Range {static_cast<std::size_t>(_container->getCount()), _batchSize}) };
 

src/lms/ui/resource/AudioFileResource.cpp

@@ -49,7 +49,7 @@ static
 std::optional<std::filesystem::path>
 getTrackPathFromTrackId(Database::TrackId trackId)
 {
-	auto transaction {LmsApp->getDbSession().createSharedTransaction()};
+	auto transaction {LmsApp->getDbSession().createReadTransaction()};
 
 	const Database::Track::pointer track {Database::Track::find(LmsApp->getDbSession(), trackId)};
 	if (!track)

src/lms/ui/resource/AudioTranscodingResource.cpp

@@ -137,7 +137,7 @@ namespace UserInterface
 
             std::filesystem::path trackPath;
             {
-                auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+                auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
                 const Database::Track::pointer track{ Database::Track::find(LmsApp->getDbSession(), *trackId) };
                 if (!track)

src/lms/ui/resource/DownloadResource.cpp

@@ -163,7 +163,7 @@ namespace UserInterface
     DownloadArtistResource::DownloadArtistResource(Database::ArtistId artistId)
         : _artistId{ artistId }
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         Database::Artist::pointer artist{ Database::Artist::find(LmsApp->getDbSession(), artistId) };
         if (artist)
@@ -172,7 +172,7 @@ namespace UserInterface
 
     std::unique_ptr<Zip::IZipper> DownloadArtistResource::createZipper()
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const auto trackResults{ Database::Track::find(LmsApp->getDbSession(), Database::Track::FindParameters {}.setArtist(_artistId).setSortMethod(Database::TrackSortMethod::DateDescAndRelease)) };
         return details::createZipper(trackResults.results);
@@ -181,7 +181,7 @@ namespace UserInterface
     DownloadReleaseResource::DownloadReleaseResource(Database::ReleaseId releaseId)
         : _releaseId{ releaseId }
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         Database::Release::pointer release{ Database::Release::find(LmsApp->getDbSession(), releaseId) };
         if (release)
@@ -193,7 +193,7 @@ namespace UserInterface
     {
         using namespace Database;
 
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         auto tracks{ Track::find(LmsApp->getDbSession(), Track::FindParameters {}.setRelease(_releaseId).setSortMethod(TrackSortMethod::Release)) };
         return details::createZipper(tracks.results);
@@ -202,7 +202,7 @@ namespace UserInterface
     DownloadTrackResource::DownloadTrackResource(Database::TrackId trackId)
         : _trackId{ trackId }
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         Database::Track::pointer track{ Database::Track::find(LmsApp->getDbSession(), trackId) };
         if (track)
@@ -211,7 +211,7 @@ namespace UserInterface
 
     std::unique_ptr<Zip::IZipper> DownloadTrackResource::createZipper()
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Database::Track::pointer track{ Database::Track::find(LmsApp->getDbSession(), _trackId) };
         if (!track)
@@ -226,7 +226,7 @@ namespace UserInterface
     DownloadTrackListResource::DownloadTrackListResource(Database::TrackListId trackListId)
         : _trackListId{ trackListId }
     {
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         const Database::TrackList::pointer trackList{ Database::TrackList::find(LmsApp->getDbSession(), trackListId) };
         if (trackList)
@@ -236,7 +236,7 @@ namespace UserInterface
     std::unique_ptr<Zip::IZipper> DownloadTrackListResource::createZipper()
     {
         using namespace Database;
-        auto transaction{ LmsApp->getDbSession().createSharedTransaction() };
+        auto transaction{ LmsApp->getDbSession().createReadTransaction() };
 
         Track::FindParameters params;
         params.setTrackList(_trackListId);