Added a scan tracker to speed up queries with high offset in very large database

src/libs/core/impl/ChildProcessManager.cpp

@@ -25,8 +25,7 @@
 
 namespace lms::core
 {
-    std::unique_ptr<IChildProcessManager>
-        createChildProcessManager(boost::asio::io_context& ioContext)
+    std::unique_ptr<IChildProcessManager> createChildProcessManager(boost::asio::io_context& ioContext)
     {
         return std::make_unique<ChildProcessManager>(ioContext);
     }
@@ -36,8 +35,7 @@ namespace lms::core
     {
     }
 
-    std::unique_ptr<IChildProcess>
-        ChildProcessManager::spawnChildProcess(const std::filesystem::path& path, const IChildProcess::Args& args)
+    std::unique_ptr<IChildProcess> ChildProcessManager::spawnChildProcess(const std::filesystem::path& path, const IChildProcess::Args& args)
     {
         return std::make_unique<ChildProcess>(_ioContext, path, args);
     }

src/libs/database/impl/Track.cpp

@@ -228,27 +228,22 @@ namespace lms::db
             .resultValue();
     }
 
-    void Track::find(Session& session, TrackId& lastRetrievedTrack, std::size_t batchSize, bool& moreResults, const std::function<void(const Track::pointer&)>& func)
+    void Track::find(Session& session, TrackId& lastRetrievedTrack, std::size_t count, const std::function<void(const Track::pointer&)>& func, MediaLibraryId library)
     {
         session.checkReadTransaction();
 
-        auto collection{ session.getDboSession().find<Track>()
+        auto query{ session.getDboSession().find<Track>()
             .orderBy("id")
             .where("id > ?").bind(lastRetrievedTrack)
-            .limit(static_cast<int>(batchSize) + 1)
-            .resultList() };
+            .limit(static_cast<int>(count)) };
 
-        moreResults = false;
+        if (library.isValid())
+            query.where("media_library_id = ?").bind(library);
+
+        auto collection{query.resultList()};
 
-        std::size_t count{};
         for (auto itResult{ collection.begin() }; itResult != collection.end(); ++itResult)
         {
-            if (count++ == batchSize)
-            {
-                moreResults = true;
-                break;
-            }
-
             func(*itResult);
             lastRetrievedTrack = (*itResult)->getId();
         }

src/libs/database/include/database/Track.hpp

@@ -110,7 +110,7 @@ namespace lms::db
         static std::size_t				getCount(Session& session);
         static pointer					findByPath(Session& session, const std::filesystem::path& p);
         static pointer 					find(Session& session, TrackId id);
-        static void                     find(Session& session, TrackId& lastRetrievedTrack, std::size_t batchSize, bool& moreResults, const std::function<void(const Track::pointer&)>& func);
+        static void                     find(Session& session, TrackId& lastRetrievedTrack, std::size_t count, const std::function<void(const Track::pointer&)>& func, MediaLibraryId library = {});
         static bool                     exists(Session& session, TrackId id);
         static std::vector<pointer>		findByRecordingMBID(Session& session, const core::UUID& MBID);
         static std::vector<pointer>		findByMBID(Session& session, const core::UUID& MBID);

src/libs/database/test/Track.cpp

@@ -68,14 +68,20 @@ namespace lms::db::tests
         ScopedTrack track1{ session, "MyTrackFile1" };
         ScopedTrack track2{ session, "MyTrackFile1" };
         ScopedTrack track3{ session, "MyTrackFile1" };
+        ScopedMediaLibrary library{ session };
+        ScopedMediaLibrary otherLibrary{ session };
+
+        {
+            auto transaction{ session.createWriteTransaction() };
+            track2.get().modify()->setMediaLibrary(library.get());
+        }
 
         {
             auto transaction{ session.createReadTransaction() };
 
-            bool moreResults;
             TrackId lastRetrievedTrackId;
             std::vector<Track::pointer> visitedTracks;
-            Track::find(session, lastRetrievedTrackId, 10, moreResults, [&](const Track::pointer& track)
+            Track::find(session, lastRetrievedTrackId, 10, [&](const Track::pointer& track)
                 {
                     visitedTracks.push_back(track);
                 });
@@ -83,40 +89,62 @@ namespace lms::db::tests
             EXPECT_EQ(visitedTracks[0]->getId(), track1.getId());
             EXPECT_EQ(visitedTracks[1]->getId(), track2.getId());
             EXPECT_EQ(visitedTracks[2]->getId(), track3.getId());
-            EXPECT_FALSE(moreResults);
             EXPECT_EQ(lastRetrievedTrackId, track3.getId());
         }
 
         {
             auto transaction{ session.createReadTransaction() };
 
-            bool moreResults;
             TrackId lastRetrievedTrackId{ track1.getId() };
             std::vector<Track::pointer> visitedTracks;
-            Track::find(session, lastRetrievedTrackId, 1, moreResults, [&](const Track::pointer& track)
+            Track::find(session, lastRetrievedTrackId, 1, [&](const Track::pointer& track)
                 {
                     visitedTracks.push_back(track);
                 });
             ASSERT_EQ(visitedTracks.size(), 1);
             EXPECT_EQ(visitedTracks[0]->getId(), track2.getId());
-            EXPECT_TRUE(moreResults);
             EXPECT_EQ(lastRetrievedTrackId, track2.getId());
         }
 
         {
             auto transaction{ session.createReadTransaction() };
 
-            bool moreResults;
             TrackId lastRetrievedTrackId{ track1.getId() };
             std::vector<Track::pointer> visitedTracks;
-            Track::find(session, lastRetrievedTrackId, 0, moreResults, [&](const Track::pointer& track)
+            Track::find(session, lastRetrievedTrackId, 0, [&](const Track::pointer& track)
                 {
                     visitedTracks.push_back(track);
                 });
             ASSERT_EQ(visitedTracks.size(), 0);
-            EXPECT_TRUE(moreResults);
             EXPECT_EQ(lastRetrievedTrackId, track1.getId());
         }
+
+        {
+            auto transaction{ session.createReadTransaction() };
+
+            TrackId lastRetrievedTrackId{};
+            std::vector<Track::pointer> visitedTracks;
+            Track::find(session, lastRetrievedTrackId, 10, [&](const Track::pointer& track)
+                {
+                    visitedTracks.push_back(track);
+                }, otherLibrary.getId());
+            ASSERT_EQ(visitedTracks.size(), 0);
+            EXPECT_EQ(lastRetrievedTrackId, TrackId{});
+        }
+
+        {
+            auto transaction{ session.createReadTransaction() };
+
+            TrackId lastRetrievedTrackId{};
+            std::vector<Track::pointer> visitedTracks;
+            Track::find(session, lastRetrievedTrackId, 10, [&](const Track::pointer& track)
+                {
+                    visitedTracks.push_back(track);
+                }, library.getId());
+            ASSERT_EQ(visitedTracks.size(), 1);
+            EXPECT_EQ(visitedTracks[0]->getId(), track2.getId());
+            EXPECT_EQ(lastRetrievedTrackId, track2.getId());
+        }
     }
 
     TEST_F(DatabaseFixture, Track_MediaLibrary)

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

@@ -99,8 +99,8 @@ namespace lms::scanner
         std::vector<Track::pointer> tracksToRemove;
 
         TrackId lastCheckedTrackID;
-        bool moreResults{ true };
-        while (moreResults)
+        bool endReached{};
+        while (!endReached)
         {
             if (_abortScan)
                 break;
@@ -108,8 +108,12 @@ namespace lms::scanner
             tracksToRemove.clear();
             {
                 auto transaction{ session.createReadTransaction() };
-                Track::find(session, lastCheckedTrackID, batchSize, moreResults, [&](const Track::pointer& track)
+
+                endReached = true;
+                Track::find(session, lastCheckedTrackID, batchSize, [&](const Track::pointer& track)
                     {
+                        endReached = false;
+
                         if (!checkFile(track->getPath()))
                             tracksToRemove.push_back(track);
 

src/libs/subsonic/impl/ClientInfo.hpp

@@ -26,6 +26,7 @@ namespace lms::api::subsonic
 {
     struct ClientInfo
     {
+        std::string ipAddress;
         std::string name;
         std::string user;
         std::string password;

src/libs/subsonic/impl/SubsonicResource.cpp

@@ -380,13 +380,16 @@ namespace lms::api::subsonic
         }
     }
 
-    ClientInfo SubsonicResource::getClientInfo(const Wt::Http::ParameterMap& parameters)
+    ClientInfo SubsonicResource::getClientInfo(const Wt::Http::Request& request)
     {
+        const auto& parameters{ request.getParameterMap() };
         ClientInfo res;
 
         if (hasParameter(parameters, "t"))
             throw TokenAuthenticationNotSupportedForLDAPUsersError{};
 
+        res.ipAddress = request.clientAddress();
+
         // Mandatory parameters
         res.name = getMandatoryParameterAs<std::string>(parameters, "c");
         res.version = getMandatoryParameterAs<ProtocolVersion>(parameters, "v");
@@ -399,7 +402,7 @@ namespace lms::api::subsonic
     RequestContext SubsonicResource::buildRequestContext(const Wt::Http::Request& request)
     {
         const Wt::Http::ParameterMap& parameters{ request.getParameterMap() };
-        const ClientInfo clientInfo{ getClientInfo(parameters) };
+        const ClientInfo clientInfo{ getClientInfo(request) };
         const db::UserId userId{ authenticateUser(request, clientInfo) };
         bool enableOpenSubsonic{ _openSubsonicDisabledClients.find(clientInfo.name) == std::cend(_openSubsonicDisabledClients) };
         bool enableDefaultCover{ _defaultCoverClients.find(clientInfo.name) != std::cend(_openSubsonicDisabledClients) };

src/libs/subsonic/impl/SubsonicResource.hpp

@@ -47,7 +47,7 @@ namespace lms::api::subsonic
             ProtocolVersion getServerProtocolVersion(const std::string& clientName) const;
 
             static void checkProtocolVersion(ProtocolVersion client, ProtocolVersion server);
-            ClientInfo getClientInfo(const Wt::Http::ParameterMap& parameters);
+            ClientInfo getClientInfo(const Wt::Http::Request& request);
             RequestContext buildRequestContext(const Wt::Http::Request& request);
             db::UserId authenticateUser(const Wt::Http::Request& request, const ClientInfo& clientInfo);
 

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

@@ -19,6 +19,10 @@
 
 #include "Searching.hpp"
 
+#include <chrono>
+#include <mutex>
+#include <map>
+
 #include "database/Artist.hpp"
 #include "database/Release.hpp"
 #include "database/Session.hpp"
@@ -34,37 +38,106 @@ namespace lms::api::subsonic
 {
     using namespace db;
 
+    namespace
+    {
+        // Search endpoints can be used to scan/sync the database
+        // This class is used to keep track of the current scans, in order to retrieve the last objectId
+        // to speed up the query of the following range (avoid the 'offset' cost)
+        template <typename ObjectId>
+        class ScanTracker
+        {
+        public:
+            ObjectId extractLastRetrievedObjectId(const ClientInfo& info, std::size_t offset);
+            void setObjectId(const ClientInfo& info, std::size_t offset, ObjectId lastRetrievedId);
+            void cleanOutdatedScanEntries();
+
+        private:
+            using ClockType = std::chrono::steady_clock;
+
+            struct Client
+            {
+                std::string clientAddress;
+                std::string clientName;
+                std::string userName;
+                std::size_t offset{};
+                auto operator<=>(const Client&) const = default;
+            };
+            struct Entry
+            {
+                ClockType::time_point timePoint;
+                ObjectId objectId;
+            };
+
+            static constexpr ClockType::duration maxEntryDuration{ std::chrono::seconds{30} };
+
+            std::mutex _mutex;
+            std::map<Client, Entry> _ongoingScans;
+        };
+
+        template<typename ObjectId>
+        ObjectId ScanTracker<ObjectId>::extractLastRetrievedObjectId(const ClientInfo& info, std::size_t offset)
+        {
+            ObjectId res;
+
+            const std::scoped_lock lock{ _mutex };
+            auto it{ _ongoingScans.find({ info.ipAddress, info.name, info.user, offset }) };
+            if (it != _ongoingScans.end())
+            {
+                res = it->second.objectId;
+                _ongoingScans.erase(it);
+            }
+
+            return res;
+        }
+
+        template<typename ObjectId>
+        void ScanTracker<ObjectId>::setObjectId(const ClientInfo& info, std::size_t offset, ObjectId lastRetrievedId)
+        {
+            const std::scoped_lock lock{ _mutex };
+            _ongoingScans[Client{ info.ipAddress, info.name, info.user, offset }] = { ClockType::now(), lastRetrievedId };
+        }
+
+        template<typename ObjectId>
+        void ScanTracker<ObjectId>::cleanOutdatedScanEntries()
+        {
+            const ClockType::time_point now{ ClockType::now() };
+
+            const std::scoped_lock lock{ _mutex };
+            std::erase_if(_ongoingScans, [&](const auto& entry) { return now > entry.second.timePoint + maxEntryDuration; });
+        }
+    }
+
     namespace
     {
         Response handleSearchRequestCommon(RequestContext& context, bool id3)
         {
             // Mandatory params
-            std::string queryString{ getMandatoryParameterAs<std::string>(context.parameters, "query") };
+            const std::string queryString{ getMandatoryParameterAs<std::string>(context.parameters, "query") };
             std::string_view query{ queryString };
 
             // Optional params
+            const std::size_t artistCount{ getParameterAs<std::size_t>(context.parameters, "artistCount").value_or(20) };
+            const std::size_t artistOffset{ getParameterAs<std::size_t>(context.parameters, "artistOffset").value_or(0) };
+            const std::size_t albumCount{ getParameterAs<std::size_t>(context.parameters, "albumCount").value_or(20) };
+            const std::size_t albumOffset{ getParameterAs<std::size_t>(context.parameters, "albumOffset").value_or(0) };
+            const std::size_t songCount{ getParameterAs<std::size_t>(context.parameters, "songCount").value_or(20) };
+            const std::size_t songOffset{ getParameterAs<std::size_t>(context.parameters, "songOffset").value_or(0) };
             const MediaLibraryId mediaLibrary{ getParameterAs<MediaLibraryId>(context.parameters, "musicFolderId").value_or(MediaLibraryId{}) };
 
+            if (artistCount > defaultMaxCountSize)
+                throw ParameterValueTooHighGenericError{ "artistCount", defaultMaxCountSize };
+            if (albumCount > defaultMaxCountSize)
+                throw ParameterValueTooHighGenericError{ "albumCount", defaultMaxCountSize };
+            if (songCount > defaultMaxCountSize)
+                throw ParameterValueTooHighGenericError{ "songCount", defaultMaxCountSize };
+
             // Symfonium adds extra ""
             if (context.clientInfo.name == "Symfonium")
                 query = core::stringUtils::stringTrim(query, "\"");
 
-            std::vector<std::string_view> keywords{ core::stringUtils::splitString(query, ' ') };
-
-            // Optional params
-            std::size_t artistCount{ getParameterAs<std::size_t>(context.parameters, "artistCount").value_or(20) };
-            std::size_t artistOffset{ getParameterAs<std::size_t>(context.parameters, "artistOffset").value_or(0) };
-            std::size_t albumCount{ getParameterAs<std::size_t>(context.parameters, "albumCount").value_or(20) };
-            std::size_t albumOffset{ getParameterAs<std::size_t>(context.parameters, "albumOffset").value_or(0) };
-            std::size_t songCount{ getParameterAs<std::size_t>(context.parameters, "songCount").value_or(20) };
-            std::size_t songOffset{ getParameterAs<std::size_t>(context.parameters, "songOffset").value_or(0) };
-
-            if (artistCount > defaultMaxCountSize)
-                throw ParameterValueTooHighGenericError{ "artistCount", defaultMaxCountSize };
-            else if (albumCount > defaultMaxCountSize)
-                throw ParameterValueTooHighGenericError{ "albumCount", defaultMaxCountSize };
-            else if (songCount > defaultMaxCountSize)
-                throw ParameterValueTooHighGenericError{ "songCount", defaultMaxCountSize };
+            std::vector<std::string_view> keywords;
+            if (!query.empty())
+                keywords = core::stringUtils::splitString(query, ' ');
 
             Response response{ Response::createOkResponse(context.serverProtocolVersion) };
             Response::Node& searchResult2Node{ response.createNode(id3 ? "searchResult3" : "searchResult2") };
@@ -102,6 +175,13 @@ namespace lms::api::subsonic
             }
 
             if (songCount > 0)
+            {
+                static ScanTracker<TrackId> currentScansInProgress;
+                currentScansInProgress.cleanOutdatedScanEntries();
+
+                TrackId lastRetrievedId;
+
+                auto findTracks{ [&]
                 {
                     Track::FindParameters params;
                     params.setKeywords(keywords);
@@ -111,7 +191,32 @@ namespace lms::api::subsonic
                     Track::find(context.dbSession, params, [&](const Track::pointer& track)
                         {
                             searchResult2Node.addArrayChild("song", createSongNode(context, track, user));
+                            lastRetrievedId = track->getId();
                         });
+                } };
+
+                if (!keywords.empty())
+                {
+                    findTracks();
+                }
+                else
+                {
+                    if (TrackId cachedLastRetrievedId{ currentScansInProgress.extractLastRetrievedObjectId(context.clientInfo, songOffset) }; cachedLastRetrievedId.isValid())
+                    {
+                        Track::find(context.dbSession, cachedLastRetrievedId, songCount, [&](const Track::pointer& track)
+                            {
+                                searchResult2Node.addArrayChild("song", createSongNode(context, track, user));
+                            }, mediaLibrary);
+                        lastRetrievedId = cachedLastRetrievedId;
+                    }
+                    else
+                    {
+                        findTracks();
+                    }
+
+                    if (lastRetrievedId.isValid())
+                        currentScansInProgress.setObjectId(context.clientInfo, songOffset + songCount, lastRetrievedId);
+                }
             }
 
             return response;
@@ -127,5 +232,4 @@ namespace lms::api::subsonic
     {
         return handleSearchRequestCommon(context, true /* id3 */);
     }
-
 }