Subsonic API: cached cluster stats for track and releases, in order to make the getGenre entrypoint efficient on large databases

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

@@ -0,0 +1,86 @@
+/*
+ * 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 "ScanStepComputeClusterStats.hpp"
+#include "services/database/Db.hpp"
+#include "services/database/Cluster.hpp"
+#include "services/database/Session.hpp"
+#include "utils/Logger.hpp"
+#include "utils/Path.hpp"
+
+namespace Scanner
+{
+    void ScanStepComputeClusterStats::process(ScanContext& context)
+    {
+        using namespace Database;
+
+        if (context.stats.nbChanges() == 0)
+            return;
+
+        Session& dbSession{ _db.getTLSSession() };
+
+        const std::size_t clusterCount{ [&] {
+            auto transaction{ dbSession.createSharedTransaction() };
+            return Cluster::getCount(dbSession);
+            }() };
+
+        context.currentStepStats.totalElems = clusterCount;
+
+        foreachSubRange(Range{ 0, clusterCount }, 100, [&](Range range)
+            {
+                const std::vector<ClusterId> clusterIds{ [&]
+                {
+                    Cluster::FindParameters params;
+                    params.setRange(range);
+
+                    {
+                        auto transaction{ dbSession.createSharedTransaction() };
+                        return std::move(Cluster::findIds(dbSession, params).results);
+                    }
+                }() };
+
+                for (const ClusterId clusterId : clusterIds)
+                {
+                    std::size_t trackCount;
+                    std::size_t releaseCount;
+
+                    {
+                        auto transaction{ dbSession.createSharedTransaction() };
+
+                        trackCount = Cluster::computeTrackCount(dbSession, clusterId);
+                        releaseCount = Cluster::computeReleaseCount(dbSession, clusterId);
+                    }
+
+                    {
+                        auto transaction{ dbSession.createUniqueTransaction() };
+
+                        auto cluster{ Cluster::find(dbSession, clusterId) };
+                        cluster.modify()->setTrackCount(trackCount);
+                        cluster.modify()->setReleaseCount(releaseCount);
+                    }
+
+                    context.currentStepStats.processedElems++;
+                }
+
+                return true;
+            });
+
+        LMS_LOG(DBUPDATER, DEBUG) << "Recomputed stats for " << clusterCount << " clusters!";
+    }
+}

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

@@ -0,0 +1,36 @@
+/*
+ * 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 "ScanStepBase.hpp"
+
+namespace Scanner
+{
+    class ScanStepComputeClusterStats : public ScanStepBase
+    {
+    public:
+        using ScanStepBase::ScanStepBase;
+
+    private:
+        ScanStep getStep() const override { return ScanStep::ComputeClusterStats; }
+        std::string_view getStepName() const override { return "Compute cluster stats"; }
+        void process(ScanContext& context) override;
+    };
+}

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

@@ -36,6 +36,7 @@
 #include "ScanStepDiscoverFiles.hpp"
 #include "ScanStepRemoveOrphanDbFiles.hpp"
 #include "ScanStepScanFiles.hpp"
+#include "ScanStepComputeClusterStats.hpp"
 
 using namespace Database;
 
@@ -357,6 +358,7 @@ ScannerService::refreshScanSettings()
 	_scanSteps.push_back(std::make_unique<ScanStepDiscoverFiles>(params));
 	_scanSteps.push_back(std::make_unique<ScanStepScanFiles>(params));
 	_scanSteps.push_back(std::make_unique<ScanStepRemoveOrphanDbFiles>(params));
+	_scanSteps.push_back(std::make_unique<ScanStepComputeClusterStats>(params));
 	_scanSteps.push_back(std::make_unique<ScanStepCheckDuplicatedDbFiles>(params));
 }