Backport pull request #18266 from jellyfin/release-12.z

Replace custom item display preferences in one transaction

Original-merge: f26319968affab72f6161cdabd0c6bf06cd7e862

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

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

1 files changed, 55 insertions, 18 deletions

diff --git a/Jellyfin.Server.Implementations/Users/DisplayPreferencesManager.cs b/Jellyfin.Server.Implementations/Users/DisplayPreferencesManager.cs
index 83ccce7441..dd3c63ae32 100644
--- a/Jellyfin.Server.Implementations/Users/DisplayPreferencesManager.cs
+++ b/Jellyfin.Server.Implementations/Users/DisplayPreferencesManager.cs
@@ -13,6 +13,8 @@ namespace Jellyfin.Server.Implementations.Users;
 /// </summary>
 public sealed class DisplayPreferencesManager : IDisplayPreferencesManager
 {
+    private const int MaxSaveAttempts = 3;
+
     private readonly IDbContextFactory<JellyfinDbContext> _dbContextFactory;
 
     /// <summary>
@@ -28,17 +30,31 @@ public sealed class DisplayPreferencesManager : IDisplayPreferencesManager
     public DisplayPreferences GetDisplayPreferences(Guid userId, Guid itemId, string client)
     {
         using var dbContext = _dbContextFactory.CreateDbContext();
-        var prefs = dbContext.DisplayPreferences
-            .Include(pref => pref.HomeSections)
-            .FirstOrDefault(pref =>
-                pref.UserId.Equals(userId) && pref.Client == client && pref.ItemId.Equals(itemId));
+        var prefs = FindDisplayPreferences(dbContext, userId, itemId, client);
+        if (prefs is not null)
+        {
+            return prefs;
+        }
 
-        if (prefs is null)
+        prefs = new DisplayPreferences(userId, itemId, client);
+        dbContext.DisplayPreferences.Add(prefs);
+        try
         {
-            prefs = new DisplayPreferences(userId, itemId, client);
-            dbContext.DisplayPreferences.Add(prefs);
             dbContext.SaveChanges();
         }
+        catch (DbUpdateException)
+        {
+            // Another request may have stored the preferences between the lookup and the insert, and the unique index
+            // rejected this one. Return the stored preferences; if there are none, the insert failed for another reason.
+            using var retryContext = _dbContextFactory.CreateDbContext();
+            var stored = FindDisplayPreferences(retryContext, userId, itemId, client);
+            if (stored is null)
+            {
+                throw;
+            }
+
+            return stored;
+        }
 
         return prefs;
     }
@@ -83,19 +99,35 @@ public sealed class DisplayPreferencesManager : IDisplayPreferencesManager
     /// <inheritdoc />
     public void SetCustomItemDisplayPreferences(Guid userId, Guid itemId, string client, Dictionary<string, string?> customPreferences)
     {
-        using var dbContext = _dbContextFactory.CreateDbContext();
-        dbContext.CustomItemDisplayPreferences.Where(prefs => prefs.UserId.Equals(userId)
-                            && prefs.ItemId.Equals(itemId)
-                            && prefs.Client == client)
-                            .ExecuteDelete();
-
-        foreach (var (key, value) in customPreferences)
+        // Another request can store one of these keys after this one's delete, and the unique index then rejects the
+        // insert. Replacing the set again gives the same result, so the replace is repeated.
+        for (var attempt = 1; ; attempt++)
         {
-            dbContext.CustomItemDisplayPreferences
-                .Add(new CustomItemDisplayPreferences(userId, itemId, client, key, value));
+            using var dbContext = _dbContextFactory.CreateDbContext();
+            using var transaction = dbContext.Database.BeginTransaction();
+            dbContext.CustomItemDisplayPreferences.Where(prefs => prefs.UserId.Equals(userId)
+                                && prefs.ItemId.Equals(itemId)
+                                && prefs.Client == client)
+                                .ExecuteDelete();
+
+            foreach (var (key, value) in customPreferences)
+            {
+                dbContext.CustomItemDisplayPreferences
+                    .Add(new CustomItemDisplayPreferences(userId, itemId, client, key, value));
+            }
+
+            try
+            {
+                dbContext.SaveChanges();
+            }
+            catch (DbUpdateException) when (attempt < MaxSaveAttempts)
+            {
+                continue;
+            }
+
+            transaction.Commit();
+            return;
         }
-
-        dbContext.SaveChanges();
     }
 
     /// <inheritdoc/>
@@ -113,4 +145,9 @@ public sealed class DisplayPreferencesManager : IDisplayPreferencesManager
         dbContext.ItemDisplayPreferences.Attach(itemDisplayPreferences).State = EntityState.Modified;
         dbContext.SaveChanges();
     }
+
+    private static DisplayPreferences? FindDisplayPreferences(JellyfinDbContext dbContext, Guid userId, Guid itemId, string client)
+        => dbContext.DisplayPreferences
+            .Include(pref => pref.HomeSections)
+            .FirstOrDefault(pref => pref.UserId.Equals(userId) && pref.Client == client && pref.ItemId.Equals(itemId));
 }