diff --git a/c#/crawler/src/Tieba/Crawl/Saver/AuthorRevisionSaver.cs b/c#/crawler/src/Tieba/Crawl/Saver/AuthorRevisionSaver.cs
index 584ecf1e..d1599c16 100644
--- a/c#/crawler/src/Tieba/Crawl/Saver/AuthorRevisionSaver.cs
+++ b/c#/crawler/src/Tieba/Crawl/Saver/AuthorRevisionSaver.cs
@@ -55,7 +55,6 @@ private static void SaveAuthorRevisions<TPost, TRevision, TValue>(
             .Select(latestRevisionProjectionFactory)
             .AsCte() // https://stackoverflow.com/questions/49854322/usage-of-for-update-in-window-function-postgres#comment86726589_49854322
             .Where(e => e.Rank == 1)
-            .AsPostgreSQL().ForNoKeyUpdateHint()
             .ToLinqToDB().AsEnumerable()
             .Join(posts, e => e.Uid, p => p.AuthorUid, (e, p) =>
             (
diff --git a/c#/crawler/src/Tieba/Crawl/Saver/Post/ReplySaver.cs b/c#/crawler/src/Tieba/Crawl/Saver/Post/ReplySaver.cs
index 45ee4b0c..d44ba4ea 100644
--- a/c#/crawler/src/Tieba/Crawl/Saver/Post/ReplySaver.cs
+++ b/c#/crawler/src/Tieba/Crawl/Saver/Post/ReplySaver.cs
@@ -1,5 +1,3 @@
-using PredicateBuilder = LinqKit.PredicateBuilder;
-
 namespace tbm.Crawler.Tieba.Crawl.Saver.Post;
 
 public class ReplySaver(
@@ -49,7 +47,7 @@ public override SaverChangeSet<ReplyPost> Save(CrawlerDbContext db)
     {
         var changeSet = Save(db, r => r.Pid,
             r => new ReplyRevision {TakenAt = r.UpdatedAt ?? r.CreatedAt, Pid = r.Pid},
-            PredicateBuilder.New<ReplyPost>(r => Posts.Keys.Contains(r.Pid)));
+            LinqKit.PredicateBuilder.New<ReplyPost>(r => Posts.Keys.Contains(r.Pid)));
 
         replyContentImageSaver.Save(db, changeSet.NewlyAdded);
         PostSaveHandlers += AuthorRevisionSaver.SaveAuthorExpGradeRevisions(db, changeSet.AllAfter).Invoke;
diff --git a/c#/crawler/src/Tieba/Crawl/Saver/Post/SubReplySaver.cs b/c#/crawler/src/Tieba/Crawl/Saver/Post/SubReplySaver.cs
index b87d556c..65909144 100644
--- a/c#/crawler/src/Tieba/Crawl/Saver/Post/SubReplySaver.cs
+++ b/c#/crawler/src/Tieba/Crawl/Saver/Post/SubReplySaver.cs
@@ -1,5 +1,3 @@
-using LinqKit;
-
 namespace tbm.Crawler.Tieba.Crawl.Saver.Post;
 
 public class SubReplySaver(
@@ -44,7 +42,7 @@ public override SaverChangeSet<SubReplyPost> Save(CrawlerDbContext db)
     {
         var changeSet = Save(db, sr => sr.Spid,
             sr => new SubReplyRevision {TakenAt = sr.UpdatedAt ?? sr.CreatedAt, Spid = sr.Spid},
-            PredicateBuilder.New<SubReplyPost>(sr => Posts.Keys.Contains(sr.Spid)));
+            LinqKit.PredicateBuilder.New<SubReplyPost>(sr => Posts.Keys.Contains(sr.Spid)));
         PostSaveHandlers += AuthorRevisionSaver.SaveAuthorExpGradeRevisions(db, changeSet.AllAfter).Invoke;
 
         return changeSet;
diff --git a/c#/crawler/src/Tieba/Crawl/Saver/SaverWithRevision.cs b/c#/crawler/src/Tieba/Crawl/Saver/SaverWithRevision.cs
index c90576e9..d545475a 100644
--- a/c#/crawler/src/Tieba/Crawl/Saver/SaverWithRevision.cs
+++ b/c#/crawler/src/Tieba/Crawl/Saver/SaverWithRevision.cs
@@ -25,21 +25,21 @@ public abstract partial class SaverWithRevision<TBaseRevision>
     protected void SaveEntitiesWithRevision<TEntity, TRevision>(
         CrawlerDbContext db,
         Func<TEntity, TRevision> revisionFactory,
-        ILookup<bool, TEntity> existingOrNewLookup,
+        ILookup<bool, TEntity> isExistingEntityLookup,
         Func<TEntity, TEntity> existingSelector,
         UserSaver.FieldChangeIgnorance? userFieldUpdateIgnorance = null,
         UserSaver.FieldChangeIgnorance? userFieldRevisionIgnorance = null)
-        where TEntity : class
+        where TEntity : RowVersionedEntity
         where TRevision : BaseRevisionWithSplitting
     {
-        db.Set<TEntity>().AddRange(existingOrNewLookup[false]); // newly added
-        var newRevisions = existingOrNewLookup[true].Select(newEntity =>
+        db.Set<TEntity>().AddRange(isExistingEntityLookup[false]); // newly added
+        var newRevisions = isExistingEntityLookup[true].Select(newEntity =>
         {
             var entityInTracking = existingSelector(newEntity);
             var entityEntry = db.Entry(entityInTracking);
 
-            // this will mutate existingEntity which is referenced by entry
-            entityEntry.CurrentValues.SetValues(newEntity);
+            entityEntry.CurrentValues.SetValues(newEntity); // mutate existingEntity that referenced by entry
+            entityEntry.Property(e => e.Version).IsModified = false; // newEntity.Version will always be default 0
 
             bool IsTimestampingFieldName(string name) => name is nameof(BasePost.LastSeenAt)
                 or nameof(TimestampedEntity.CreatedAt) or nameof(TimestampedEntity.UpdatedAt);
diff --git a/c#/crawler/src/Worker/RetryCrawlWorker.cs b/c#/crawler/src/Worker/RetryCrawlWorker.cs
index 6ba72f28..329d4012 100644
--- a/c#/crawler/src/Worker/RetryCrawlWorker.cs
+++ b/c#/crawler/src/Worker/RetryCrawlWorker.cs
@@ -2,7 +2,7 @@ namespace tbm.Crawler.Worker;
 
 public class RetryCrawlWorker(
     ILogger<RetryCrawlWorker> logger,
-    IIndex<CrawlerLocks.Type, CrawlerLocks> registeredLocksLookup,
+    IIndex<CrawlerLocks.Type, CrawlerLocks> registeredLocksKeyByType,
     CrawlPost crawlPost,
     Func<Owned<CrawlerDbContext.NewDefault>> dbContextDefaultFactory,
     Func<Owned<ThreadLateCrawlFacade.New>> threadLateCrawlFacadeFactory,
@@ -16,7 +16,7 @@ protected override async Task DoWork(CancellationToken stoppingToken)
         foreach (var lockType in Enum.GetValues<CrawlerLocks.Type>())
         {
             if (stoppingToken.IsCancellationRequested) return;
-            var failed = registeredLocksLookup[lockType].RetryAllFailed();
+            var failed = registeredLocksKeyByType[lockType].RetryAllFailed();
             if (failed.Count == 0) continue; // skip current lock type if there's nothing needs to retry
             if (lockType == CrawlerLocks.Type.ThreadLate)
             {