Tentative fix for bad query perf with recent sqlite versions: limit 1 seems to be culprit

src/libs/database/impl/Db.cpp

@@ -114,7 +114,7 @@ namespace lms::db
 
             std::string table;
             std::string foreignTable;
-            // see https://www.sqlite.org/pragma.html#pragma_foreign_key_check for exepcted result
+            // see https://www.sqlite.org/pragma.html#pragma_foreign_key_check for expected result
             while (statement->nextRow())
             {
                 foreignKeyConstraintsPassed = false;
@@ -132,6 +132,57 @@ namespace lms::db
 
             return foreignKeyConstraintsPassed;
         }
+
+        std::optional<int> getPageSize(Wt::Dbo::SqlConnection& connection)
+        {
+            auto statement = connection.prepareStatement("PRAGMA page_size");
+            statement->execute();
+
+            std::optional<int> res;
+            while (statement->nextRow())
+            {
+                assert(!res);
+                int value{};
+                if (statement->getResult(0, &value))
+                    res = value;
+                break;
+            }
+
+            return res;
+        }
+
+        std::optional<int> getCacheSize(Wt::Dbo::SqlConnection& connection)
+        {
+            auto statement = connection.prepareStatement("PRAGMA cache_size");
+            statement->execute();
+
+            std::optional<int> res;
+            while (statement->nextRow())
+            {
+                assert(!res);
+                int value{};
+                if (statement->getResult(0, &value))
+                    res = value;
+                break;
+            }
+
+            return res;
+        }
+
+        void getCompileOptions(Wt::Dbo::SqlConnection& connection, std::function<void(std::string_view compileOption)> callback)
+        {
+            auto statement = connection.prepareStatement("PRAGMA compile_options");
+            statement->execute();
+
+            std::string res;
+            while (statement->nextRow())
+            {
+                res.clear();
+
+                if (statement->getResult(0, &res, static_cast<int>(res.capacity())))
+                    callback(res);
+            }
+        }
     } // namespace
 
     std::unique_ptr<IDb> createDb(const std::filesystem::path& dbPath, std::size_t connectionCount)
@@ -157,6 +208,13 @@ namespace lms::db
 
         _connectionPool = std::move(connectionPool);
 
+        executeSql("PRAGMA temp_store=MEMORY");
+        executeSql("PRAGMA cache_size=-8000");
+        executeSql("PRAGMA automatic_index=0");
+
+        logPageSize();
+        logCacheSize();
+        logCompileOptions();
         if (checkType == "quick")
         {
             performQuickCheck();
@@ -199,6 +257,34 @@ namespace lms::db
         return *tlsSession;
     }
 
+    void Db::logPageSize()
+    {
+        ScopedConnection connection{ *_connectionPool };
+        const std::optional<int> pageSize{ getPageSize(*connection) };
+
+        if (pageSize)
+            LMS_LOG(DB, INFO, "Page size set to " << *pageSize);
+    }
+
+    void Db::logCacheSize()
+    {
+        ScopedConnection connection{ *_connectionPool };
+        const std::optional<int> cacheSize{ getCacheSize(*connection) };
+
+        if (cacheSize)
+            LMS_LOG(DB, INFO, "Cache size set to " << *cacheSize);
+    }
+
+    void Db::logCompileOptions()
+    {
+        ScopedConnection connection{ *_connectionPool };
+
+        LMS_LOG(DB, INFO, "Sqlite3 compile options:");
+        getCompileOptions(*connection, [](std::string_view compileOption) {
+            LMS_LOG(DB, INFO, compileOption);
+        });
+    }
+
     void Db::performQuickCheck()
     {
         ScopedConnection connection{ *_connectionPool };

src/libs/database/impl/Db.hpp

@@ -49,6 +49,9 @@ namespace lms::db
         core::RecursiveSharedMutex& getMutex() { return _sharedMutex; }
         Wt::Dbo::SqlConnectionPool& getConnectionPool() { return *_connectionPool; }
 
+        void logPageSize();
+        void logCacheSize();
+        void logCompileOptions();
         void performQuickCheck();
         void performIntegrityCheck();
         void performForeignKeyConstraintsCheck();

src/libs/database/impl/Utils.hpp

@@ -58,7 +58,8 @@ namespace lms::db::utils
         if (range)
         {
             query.limit(static_cast<int>(range->size));
-            query.offset(static_cast<int>(range->offset));
+            if (range->offset != 0)
+                query.offset(static_cast<int>(range->offset));
         }
     }
 

src/libs/database/impl/objects/TrackEmbeddedImage.cpp

@@ -91,7 +91,7 @@ namespace lms::db
                 }
 
                 if (params.imageType.has_value())
-                    query.where("+t_e_i_l.type = ?").bind(params.imageType.value()); // hack: type is a bad way to reduce the result space
+                    query.where("t_e_i_l.type = ?").bind(params.imageType.value());
             }
 
             switch (params.sortMethod)

src/libs/services/scanner/impl/steps/ScanStepAssociateReleaseImages.cpp

@@ -142,9 +142,10 @@ namespace lms::scanner
                 params.setRelease(release->getId());
                 params.setImageType(db::ImageType::FrontCover);
                 params.setSortMethod(db::TrackEmbeddedImageSortMethod::DiscNumberThenTrackNumberThenSizeDesc);
-                params.setRange(db::Range{ .offset = 0, .size = 1 });
+                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) {
-
+                    if (!artwork)
-                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) { artwork = db::Artwork::find(session, image->getId()); });
+                        artwork = db::Artwork::find(session, image->getId());
+                });
             }
 
             if (artwork)
@@ -156,9 +157,10 @@ namespace lms::scanner
                 params.setRelease(release->getId());
                 params.setImageType(db::ImageType::Media);
                 params.setSortMethod(db::TrackEmbeddedImageSortMethod::DiscNumberThenTrackNumberThenSizeDesc);
-                params.setRange(db::Range{ .offset = 0, .size = 1 });
+                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) {
-
+                    if (!artwork)
-                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) { artwork = db::Artwork::find(session, image->getId()); });
+                        artwork = db::Artwork::find(session, image->getId());
+                });
             }
 
             return artwork;

src/libs/services/scanner/impl/steps/ScanStepAssociateTrackImages.cpp

@@ -65,8 +65,11 @@ namespace lms::scanner
                 params.setTrack(track->getId());
                 params.setImageType(db::ImageType::FrontCover);
                 params.setSortMethod(db::TrackEmbeddedImageSortMethod::SizeDesc);
-                params.setRange(db::Range{ .offset = 0, .size = 1 });
+
-                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) { res = db::Artwork::find(session, image->getId()); });
+                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) {
+                    if (!res)
+                        res = db::Artwork::find(session, image->getId());
+                });
             }
 
             if (res)
@@ -92,8 +95,11 @@ namespace lms::scanner
                 params.setTrack(track->getId());
                 params.setImageType(db::ImageType::Media);
                 params.setSortMethod(db::TrackEmbeddedImageSortMethod::SizeDesc);
-                params.setRange(db::Range{ .offset = 0, .size = 1 });
+
-                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) { res = db::Artwork::find(session, image->getId()); });
+                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) {
+                    if (!res)
+                        res = db::Artwork::find(session, image->getId());
+                });
             }
 
             if (res)
@@ -111,8 +117,11 @@ namespace lms::scanner
                 params.setDiscNumber(discNumber);
                 params.setImageType(db::ImageType::Media);
                 params.setSortMethod(db::TrackEmbeddedImageSortMethod::TrackNumberThenSizeDesc);
-                params.setRange(db::Range{ .offset = 0, .size = 1 });
+
-                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) { res = db::Artwork::find(session, image->getId()); });
+                db::TrackEmbeddedImage::find(session, params, [&](const db::TrackEmbeddedImage::pointer& image) {
+                    if (!res)
+                        res = db::Artwork::find(session, image->getId());
+                });
             }
 
             return res;