No parallel updates when in transaction. (#915)

* No parallel updates when in transaction.

* Option for clustering.

backend/src/Squidex.Domain.Apps.Entities.MongoDb/Contents/MongoContentRepository.cs

@@ -26,6 +26,7 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Contents
     {
         private readonly MongoContentCollection collectionComplete;
         private readonly MongoContentCollection collectionPublished;
+        private readonly ContentOptions options;
         private readonly IMongoDatabase database;
         private readonly IAppProvider appProvider;
 
@@ -42,7 +43,9 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Contents
         public MongoContentRepository(IMongoDatabase database, IAppProvider appProvider,
             IOptions<ContentOptions> options)
         {
+            this.appProvider = appProvider;
             this.database = database;
+            this.options = options.Value;
 
             collectionComplete =
                 new MongoContentCollection("States_Contents_All3", database,
@@ -51,8 +54,6 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Contents
             collectionPublished =
                 new MongoContentCollection("States_Contents_Published3", database,
                     ReadPreference.Secondary, options.Value.OptimizeForSelfHosting);
-
-            this.appProvider = appProvider;
         }
 
         public async Task InitializeAsync(
@@ -64,7 +65,7 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Contents
             var clusterVersion = await database.GetMajorVersionAsync(ct);
             var clusteredAsReplica = database.Client.Cluster.Description.Type == ClusterType.ReplicaSet;
 
-            CanUseTransactions = clusteredAsReplica && clusterVersion >= 4;
+            CanUseTransactions = clusteredAsReplica && clusterVersion >= 4 && options.UseTransactions;
         }
 
         public IAsyncEnumerable<IContentEntity> StreamAll(DomainId appId, HashSet<DomainId>? schemaIds,

backend/src/Squidex.Domain.Apps.Entities.MongoDb/Contents/MongoContentRepository_SnapshotStore.cs

@@ -106,9 +106,8 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Contents
                     // Make an update with full transaction support to be more consistent.
                     await session.WithTransactionAsync(async (session, ct) =>
                     {
-                        await Task.WhenAll(
-                            UpsertVersionedCompleteAsync(session, job, ct),
-                            UpsertVersionedPublishedAsync(session, job, ct));
+                        await UpsertVersionedCompleteAsync(session, job, ct);
+                        await UpsertVersionedPublishedAsync(session, job, ct);
                         return true;
                     }, null, ct);
                 }

backend/src/Squidex.Domain.Apps.Entities/Contents/ContentOptions.cs

@@ -13,6 +13,8 @@ namespace Squidex.Domain.Apps.Entities.Contents
 
         public bool OptimizeForSelfHosting { get; set; }
 
+        public bool UseTransactions { get; set; }
+
         public int DefaultPageSize { get; set; } = 200;
 
         public int MaxResults { get; set; } = 200;

backend/src/Squidex/appsettings.json

@@ -234,6 +234,11 @@
         // Creates one database per app and one collection per schema. Slows down inserts, but you can create custom indexes.
         "optimizeForSelfHosting": false,
 
+        // False to not use transactions. Improves performance.
+        //
+        // Warning: Can cause consistency issues.
+        "useTransactions": true,
+
         // The default page size if not specified by a query.
         //
         // Warning: Can slow down queries if increased.