Removing key from object store when collection object it empty

libs/server/Custom/CustomObjectBase.cs

@@ -187,13 +187,15 @@ public sealed override void DoSerialize(BinaryWriter writer)
         public abstract override void Dispose();
 
         /// <inheritdoc />
-        public abstract void Operate(byte subCommand, ReadOnlySpan<byte> input, ref (IMemoryOwner<byte>, int) output);
+        public abstract void Operate(byte subCommand, ReadOnlySpan<byte> input, ref (IMemoryOwner<byte>, int) output, out bool removeKey);
 
         /// <inheritdoc />
-        public sealed override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange)
+        public sealed override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange, out bool removeKey)
         {
             var header = (RespInputHeader*)input.ToPointer();
             sizeChange = 0;
+            removeKey = false;
+
             switch (header->cmd)
             {
                 // Scan Command
@@ -207,11 +209,12 @@ public sealed override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMe
                     break;
                 default:
                     (IMemoryOwner<byte> Memory, int Length) outp = (output.Memory, 0);
-                    Operate(header->SubId, input.AsReadOnlySpan().Slice(RespInputHeader.Size), ref outp);
+                    Operate(header->SubId, input.AsReadOnlySpan().Slice(RespInputHeader.Size), ref outp, out removeKey);
                     output.Memory = outp.Memory;
                     output.Length = outp.Length;
                     break;
             }
+
             return true;
         }
     }

libs/server/Objects/Hash/HashObject.cs

@@ -108,8 +108,10 @@ public override void Dispose() { }
         public override GarnetObjectBase Clone() => new HashObject(hash, Expiration, Size);
 
         /// <inheritdoc />
-        public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange)
+        public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange, out bool removeKey)
         {
+            removeKey = false;
+
             fixed (byte* _input = input.AsSpan())
             fixed (byte* _output = output.SpanByte.AsSpan())
             {
@@ -183,6 +185,8 @@ public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory ou
 
                 sizeChange = this.Size - previousSize;
             }
+
+            removeKey = hash.Count == 0;
             return true;
         }
 

libs/server/Objects/List/ListObject.cs

@@ -126,11 +126,13 @@ public override void Dispose() { }
         public override GarnetObjectBase Clone() => new ListObject(list, Expiration, Size);
 
         /// <inheritdoc />
-        public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange)
+        public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange, out bool removeKey)
         {
             fixed (byte* _input = input.AsSpan())
             fixed (byte* _output = output.SpanByte.AsSpan())
             {
+                removeKey = false;
+
                 var header = (RespInputHeader*)_input;
                 if (header->type != GarnetObjectType.List)
                 {
@@ -185,6 +187,8 @@ public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory ou
 
                 sizeChange = this.Size - previousSize;
             }
+
+            removeKey = list.Count == 0;
             return true;
         }
 

libs/server/Objects/Set/SetObject.cs

@@ -104,7 +104,7 @@ public override void Dispose() { }
         public override GarnetObjectBase Clone() => new SetObject(set, Expiration, Size);
 
         /// <inheritdoc />
-        public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange)
+        public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange, out bool removeKey)
         {
             fixed (byte* _input = input.AsSpan())
             fixed (byte* _output = output.SpanByte.AsSpan())
@@ -147,6 +147,8 @@ public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory ou
                 }
                 sizeChange = this.Size - prevSize;
             }
+
+            removeKey = set.Count == 0;
             return true;
         }
 

libs/server/Objects/SortedSet/SortedSetObject.cs

@@ -177,7 +177,7 @@ public override void Dispose() { }
         public override GarnetObjectBase Clone() => new SortedSetObject(sortedSet, sortedSetDict, Expiration, Size);
 
         /// <inheritdoc />
-        public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange)
+        public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange, out bool removeKey)
         {
             fixed (byte* _input = input.AsSpan())
             fixed (byte* _output = output.SpanByte.AsSpan())
@@ -271,6 +271,8 @@ public override unsafe bool Operate(ref SpanByte input, ref SpanByteAndMemory ou
                 }
                 sizeChange = this.Size - previouseSize;
             }
+
+            removeKey = sortedSetDict.Count == 0;
             return true;
         }
 

libs/server/Objects/Types/GarnetObjectBase.cs

@@ -116,7 +116,7 @@ public void CopyUpdate(ref IGarnetObject oldValue, ref IGarnetObject newValue, b
         public abstract GarnetObjectBase Clone();
 
         /// <inheritdoc />
-        public abstract bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange);
+        public abstract bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange, out bool removeKey);
 
         /// <inheritdoc />
         public abstract void Dispose();

libs/server/Objects/Types/IGarnetObject.cs

@@ -34,8 +34,9 @@ public interface IGarnetObject : IDisposable
         /// <param name="input"></param>
         /// <param name="output"></param>
         /// <param name="sizeChange"></param>
+        /// <param name="removeKey"></param>
         /// <returns></returns>
-        bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange);
+        bool Operate(ref SpanByte input, ref SpanByteAndMemory output, out long sizeChange, out bool removeKey);
 
         /// <summary>
         /// Serializer

libs/server/Resp/Objects/ListCommands.cs

@@ -846,6 +846,13 @@ public unsafe bool ListSet<TGarnetApi>(int count, byte* ptr, ref TGarnetApi stor
                         var objOutputHeader = ProcessOutputWithHeader(outputFooter.spanByteAndMemory);
                         ptr += objOutputHeader.bytesDone;
                         break;
+                    case GarnetStatus.NOTFOUND:
+                        var tokens = ReadLeftToken(count - 1, ref ptr);
+                        if (tokens < count - 1)
+                            return false;
+                        while (!RespWriteUtils.WriteError(CmdStrings.RESP_ERR_GENERIC_NOSUCHKEY, ref dcurr, dend))
+                            SendAndReset();
+                        break;
                 }
             }
 

libs/server/Resp/Objects/SortedSetCommands.cs

@@ -848,6 +848,7 @@ private unsafe bool SortedSetIncrement<TGarnetApi>(int count, byte* ptr, ref TGa
                 ReadOnlySpan<byte> errorMessage = default;
                 switch (status)
                 {
+                    case GarnetStatus.NOTFOUND:
                     case GarnetStatus.OK:
                         //verifying length of outputFooter
                         if (outputFooter.spanByteAndMemory.Length == 0)
@@ -869,10 +870,6 @@ private unsafe bool SortedSetIncrement<TGarnetApi>(int count, byte* ptr, ref TGa
                             ptr += objOutputHeader.bytesDone;
                         }
                         break;
-                    case GarnetStatus.NOTFOUND:
-                        while (!RespWriteUtils.WriteDirect(CmdStrings.RESP_ERRNOTFOUND, ref dcurr, dend))
-                            SendAndReset();
-                        break;
                 }
 
                 if (errorMessage != default)

libs/server/Storage/Functions/MainStore/RMWMethods.cs

@@ -717,11 +717,12 @@ public bool CopyUpdater(ref SpanByte key, ref SpanByte input, ref SpanByte oldVa
         }
 
         /// <inheritdoc />
-        public void PostCopyUpdater(ref SpanByte key, ref SpanByte input, ref SpanByte oldValue, ref SpanByte newValue, ref SpanByteAndMemory output, ref RMWInfo rmwInfo)
+        public bool PostCopyUpdater(ref SpanByte key, ref SpanByte input, ref SpanByte oldValue, ref SpanByte newValue, ref SpanByteAndMemory output, ref RMWInfo rmwInfo)
         {
             functionsState.watchVersionMap.IncrementVersion(rmwInfo.KeyHash);
             if (functionsState.appendOnlyFile != null)
                 WriteLogRMW(ref key, ref input, ref oldValue, rmwInfo.Version, rmwInfo.SessionID);
+            return true;
         }
     }
 }

libs/server/Storage/Functions/ObjectStore/RMWMethods.cs

@@ -27,7 +27,7 @@ public bool InitialUpdater(ref byte[] key, ref SpanByte input, ref IGarnetObject
                 byte objectId = (byte)((byte)type - CustomCommandManager.StartOffset);
                 value = functionsState.customObjectCommands[objectId].factory.Create((byte)type);
             }
-            value.Operate(ref input, ref output.spanByteAndMemory, out _);
+            value.Operate(ref input, ref output.spanByteAndMemory, out _, out _);
             return true;
         }
 
@@ -74,7 +74,7 @@ bool InPlaceUpdaterWorker(ref byte[] key, ref SpanByte input, ref IGarnetObject
             switch (header->type)
             {
                 case GarnetObjectType.Expire:
-                    ExpireOption optionType = (ExpireOption)(*(input.ToPointer() + RespInputHeader.Size));
+                    var optionType = (ExpireOption)(*(input.ToPointer() + RespInputHeader.Size));
                     bool expiryExists = (value.Expiration > 0);
                     return EvaluateObjectExpireInPlace(optionType, expiryExists, ref input, ref value, ref output);
                 case GarnetObjectType.Persist:
@@ -87,7 +87,15 @@ bool InPlaceUpdaterWorker(ref byte[] key, ref SpanByte input, ref IGarnetObject
                         CopyDefaultResp(CmdStrings.RESP_RETURN_VAL_0, ref output.spanByteAndMemory);
                     return true;
                 default:
-                    return value.Operate(ref input, ref output.spanByteAndMemory, out sizeChange);
+                    var operateSuccessful = value.Operate(ref input, ref output.spanByteAndMemory, out sizeChange,
+                        out var removeKey);
+                    if (removeKey)
+                    {
+                        rmwInfo.Action = RMWAction.ExpireAndStop;
+                        return false;
+                    }
+
+                    return operateSuccessful;
             }
         }
 
@@ -110,18 +118,21 @@ public bool CopyUpdater(ref byte[] key, ref SpanByte input, ref IGarnetObject ol
         }
 
         /// <inheritdoc />
-        public void PostCopyUpdater(ref byte[] key, ref SpanByte input, ref IGarnetObject oldValue, ref IGarnetObject value, ref GarnetObjectStoreOutput output, ref RMWInfo rmwInfo)
+        public bool PostCopyUpdater(ref byte[] key, ref SpanByte input, ref IGarnetObject oldValue, ref IGarnetObject value, ref GarnetObjectStoreOutput output, ref RMWInfo rmwInfo)
         {
+            // We're performing the object update here (and not in CopyUpdater) so that we are guaranteed that 
+            // the record was CASed into the hash chain before it gets modified
             oldValue.CopyUpdate(ref oldValue, ref value, rmwInfo.RecordInfo.IsInNewVersion);
 
             var header = (RespInputHeader*)input.ToPointer();
             functionsState.watchVersionMap.IncrementVersion(rmwInfo.KeyHash);
+
             switch (header->type)
             {
                 case GarnetObjectType.Expire:
-                    ExpireOption optionType = (ExpireOption)(*(input.ToPointer() + RespInputHeader.Size));
-                    bool expiryExists = (value.Expiration > 0);
-                    EvaluateObjectExpireInPlace(optionType, expiryExists, ref input, ref value, ref output);
+                    var expireOption = (ExpireOption)(*(input.ToPointer() + RespInputHeader.Size));
+                    var expiryExists = (value.Expiration > 0);
+                    EvaluateObjectExpireInPlace(expireOption, expiryExists, ref input, ref value, ref output);
                     break;
                 case GarnetObjectType.Persist:
                     if (value.Expiration > 0)
@@ -133,14 +144,20 @@ public void PostCopyUpdater(ref byte[] key, ref SpanByte input, ref IGarnetObjec
                         CopyDefaultResp(CmdStrings.RESP_RETURN_VAL_0, ref output.spanByteAndMemory);
                     break;
                 default:
-                    value.Operate(ref input, ref output.spanByteAndMemory, out _);
+                    value.Operate(ref input, ref output.spanByteAndMemory, out _, out var removeKey);
+                    if (removeKey)
+                    {
+                        rmwInfo.Action = RMWAction.ExpireAndStop;
+                        return false;
+                    }
                     break;
             }
 
             functionsState.objectStoreSizeTracker?.AddTrackedSize(MemoryUtils.CalculateKeyValueSize(key, value));
 
             if (functionsState.appendOnlyFile != null)
                 WriteLogRMW(ref key, ref input, ref oldValue, rmwInfo.Version, rmwInfo.SessionID);
+            return true;
         }
     }
 }

libs/server/Storage/Functions/ObjectStore/ReadMethods.cs

@@ -28,7 +28,7 @@ public bool SingleReader(ref byte[] key, ref SpanByte input, ref IGarnetObject v
                 return true;
             }
 
-            return value.Operate(ref input, ref dst.spanByteAndMemory, out _);
+            return value.Operate(ref input, ref dst.spanByteAndMemory, out _, out _);
         }
 
         /// <inheritdoc />
@@ -52,7 +52,7 @@ public bool ConcurrentReader(ref byte[] key, ref SpanByte input, ref IGarnetObje
                     CopyRespNumber(ttlValue, ref dst.spanByteAndMemory);
                     return true;
                 }
-                return value.Operate(ref input, ref dst.spanByteAndMemory, out _);
+                return value.Operate(ref input, ref dst.spanByteAndMemory, out _, out _);
             }
 
             dst.garnetObject = value;

libs/server/Storage/Session/ObjectStore/Common.cs

@@ -30,10 +30,7 @@ unsafe GarnetStatus RMWObjectStoreOperation<TObjectContext>(byte[] key, ArgSlice
             Debug.Assert(_output.spanByteAndMemory.IsSpanByte);
 
 
-            if (!status.Record.Created && !status.Record.CopyUpdated && !status.Record.InPlaceUpdated)
-                return GarnetStatus.NOTFOUND;
-
-            return GarnetStatus.OK;
+            return status.Found || status.Record.Created ? GarnetStatus.OK : GarnetStatus.NOTFOUND;
         }
 
         /// <summary>
@@ -57,10 +54,7 @@ GarnetStatus RMWObjectStoreOperationWithOutput<TObjectContext>(byte[] key, ArgSl
             if (status.IsPending)
                 CompletePendingForObjectStoreSession(ref status, ref outputFooter, ref objectStoreContext);
 
-            if (!status.Record.Created && !status.Record.CopyUpdated && !status.Record.InPlaceUpdated)
-                return GarnetStatus.NOTFOUND;
-
-            return GarnetStatus.OK;
+            return status.Found || status.Record.Created ? GarnetStatus.OK : GarnetStatus.NOTFOUND;
         }
 
         /// <summary>

libs/storage/Tsavorite/cs/benchmark/SessionFunctions.cs

@@ -72,7 +72,7 @@ public bool CopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Va
             return true;
         }
 
-        public void PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo) { }
+        public bool PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo) => true;
 
         public bool NeedInitialUpdate(ref Key key, ref Input input, ref Output output, ref RMWInfo rmwInfo) => true;
 

libs/storage/Tsavorite/cs/src/core/Allocator/AllocatorScan.cs

@@ -338,7 +338,7 @@ public void PostSingleWriter(ref Key key, ref Input input, ref Value src, ref Va
 
             public bool NeedCopyUpdate(ref Key key, ref Input input, ref Value oldValue, ref Output output, ref RMWInfo rmwInfo) => true;
             public bool CopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo, ref RecordInfo recordInfo) => true;
-            public void PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo) { }
+            public bool PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo) => true;
 
             public bool NeedInitialUpdate(ref Key key, ref Input input, ref Output output, ref RMWInfo rmwInfo) => true;
             public bool InitialUpdater(ref Key key, ref Input input, ref Value value, ref Output output, ref RMWInfo rmwInfo, ref RecordInfo recordInfo) => true;

libs/storage/Tsavorite/cs/src/core/ClientSession/SessionFunctionsWrapper.cs

@@ -87,10 +87,10 @@ public bool CopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Va
             => _clientSession.functions.CopyUpdater(ref key, ref input, ref oldValue, ref newValue, ref output, ref rmwInfo, ref recordInfo);
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo, ref RecordInfo recordInfo)
+        public bool PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo, ref RecordInfo recordInfo)
         {
             recordInfo.SetDirtyAndModified();
-            _clientSession.functions.PostCopyUpdater(ref key, ref input, ref oldValue, ref newValue, ref output, ref rmwInfo);
+            return _clientSession.functions.PostCopyUpdater(ref key, ref input, ref oldValue, ref newValue, ref output, ref rmwInfo);
         }
         #endregion CopyUpdater
 

libs/storage/Tsavorite/cs/src/core/Compaction/LogCompactionFunctions.cs

@@ -35,7 +35,7 @@ public void PostSingleDeleter(ref Key key, ref DeleteInfo deleteInfo) { }
 
         public bool CopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo, ref RecordInfo recordInfo) => true;
 
-        public void PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo) { }
+        public bool PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo) => true;
 
         public bool InitialUpdater(ref Key key, ref Input input, ref Value value, ref Output output, ref RMWInfo rmwInfo, ref RecordInfo recordInfo) => true;
         public void PostInitialUpdater(ref Key key, ref Input input, ref Value value, ref Output output, ref RMWInfo rmwInfo) { }

libs/storage/Tsavorite/cs/src/core/Index/Interfaces/ISessionFunctions.cs

@@ -163,7 +163,10 @@ public interface ISessionFunctions<Key, Value, Input, Output, Context>
         /// <param name="newValue">The destination to be updated; because this is an copy to a new location, there is no previous value there.</param>
         /// <param name="output">The location where <paramref name="newValue"/> is to be copied</param>
         /// <param name="rmwInfo">Information about this update operation and its context</param>
-        void PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo);
+        /// <returns>This is the only Post* method that returns non-void. The bool functions the same as CopyUpdater; this is because we do not want to modify
+        /// objects in-memory until we know the "insert at tail" is successful. Therefore, we allow a false return as a signal to inspect <paramref name="rmwInfo.Action"/>
+        /// and handle <see cref="RMWAction.ExpireAndStop"/>.</returns>
+        bool PostCopyUpdater(ref Key key, ref Input input, ref Value oldValue, ref Value newValue, ref Output output, ref RMWInfo rmwInfo);
         #endregion CopyUpdater
 
         #region InPlaceUpdater