Backport pull request #18196 from jellyfin/release-12.z

Skip statistics on an empty library and refresh them after every scan

Original-merge: 83b89218e5

Merged-by: crobibero <cody@robibe.ro>

Backported-by: Cody Robibero <cody@robibe.ro>

Emby.Server.Implementations/Data/RefreshDatabaseStatisticsPostScanTask.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Jellyfin.Database.Implementations;
+using MediaBrowser.Controller.Library;
+
+namespace Emby.Server.Implementations.Data;
+
+/// <summary>
+/// Refreshes the database statistics after every library scan.
+/// </summary>
+/// <remarks>
+/// The scheduled optimization skips itself while a scan runs, so without this the first scan of a new server
+/// leaves every query planned for an empty library until the next scheduled run.
+/// </remarks>
+public class RefreshDatabaseStatisticsPostScanTask : ILibraryPostScanTask
+{
+    private readonly IJellyfinDatabaseProvider _databaseProvider;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="RefreshDatabaseStatisticsPostScanTask"/> class.
+    /// </summary>
+    /// <param name="databaseProvider">The database provider.</param>
+    public RefreshDatabaseStatisticsPostScanTask(IJellyfinDatabaseProvider databaseProvider)
+    {
+        _databaseProvider = databaseProvider;
+    }
+
+    /// <inheritdoc />
+    public async Task Run(IProgress<double> progress, CancellationToken cancellationToken)
+    {
+        await _databaseProvider.RefreshStatistics(cancellationToken).ConfigureAwait(false);
+        progress.Report(100);
+    }
+}