Support for Diskless Replication (#997)

* expose diskless replication parameters

* refactor/cleanup legacy ReplicaSyncSession

* add interface to support diskless replication session and aof tasks

* core diskless replication implementation

* expose diskless replication API

* adding test for diskless replication

* update gcs extension to clearly mark logging progress

* fix gcs dispose on diskless attach, call dispose of replicationSyncManager, add more logging

* complete first diskless replication test

* fix iterator check for null when empty store

* fix iterator for object store cluster sync

* add simple diskless sync test

* cleanup code

* replica fall behind test

* wip

* register cts at wait for sync completion

* add db version alignment test

* avoid using close lock for leader based syncing

* truncate AOF after streaming checkpoint is taken

* add tests for failover with diskless replication

* fix formatting and conversion to IPEndpoint

* fix RepCommandsTests

* dispose aofSyncTask if failed to add to AofSyncTaskStore

* overload dispose ReplicaSyncSession

* explicitly dispose gcs used for full sync at replicaSyncSession sync

* dispose gcs once on return

* code cleanup

* update tests to provide more context logging

* add more comprehensive logging of syncMetadata

* add timeout for streaming checkpoint

* add clusterTimeout for diskless repl tests

* some more logging

* cleanup and refactor code

* truncate AOF only when main-memory-replication is switched on

* adding logging for cancellation when streaming

* split checkpoint commit marker to allow for disk checkpoints

* update sync metadata log message

* add progress based timeout implementation

* deprecate main-memory-replication

benchmark/BDN.benchmark/Operations/OperationsBase.cs

@@ -63,7 +63,7 @@ public virtual void GlobalSetup()
             {
                 opts.EnableAOF = true;
                 opts.UseAofNullDevice = true;
-                opts.MainMemoryReplication = true;
+                opts.FastAofTruncate = true;
                 opts.CommitFrequencyMs = -1;
                 opts.AofPageSize = "128m";
                 opts.AofMemorySize = "256m";

libs/client/ClientSession/GarnetClientSessionIncremental.cs

@@ -12,8 +12,15 @@
 
 namespace Garnet.client
 {
+    enum IncrementalSendType : byte
+    {
+        MIGRATE,
+        SYNC
+    }
+
     public sealed unsafe partial class GarnetClientSession : IServerHook, IMessageConsumer
     {
+        IncrementalSendType ist;
         bool isMainStore;
         byte* curr, head;
         int keyValuePairCount;
@@ -183,9 +190,9 @@ private void TrackIterationProgress(int keyCount, int size, bool completed = fal
             var duration = TimeSpan.FromTicks(Stopwatch.GetTimestamp() - lastLog);
             if (completed || lastLog == 0 || duration >= iterationProgressFreq)
             {
-                logger?.LogTrace("[{op}]: isMainStore:({storeType}) totalKeyCount:({totalKeyCount}), totalPayloadSize:({totalPayloadSize} KB)",
-                    completed ? "COMPLETED" : "MIGRATING",
-                    isMainStore,
+                logger?.LogTrace("[{op}]: store:({storeType}) totalKeyCount:({totalKeyCount}), totalPayloadSize:({totalPayloadSize} KB)",
+                    completed ? "COMPLETED" : ist,
+                    isMainStore ? "MAIN STORE" : "OBJECT STORE",
                     totalKeyCount.ToString("N0"),
                     ((long)((double)totalPayloadSize / 1024)).ToString("N0"));
                 lastLog = Stopwatch.GetTimestamp();

libs/client/ClientSession/GarnetClientSessionMigrationExtensions.cs

@@ -176,6 +176,7 @@ public void SetClusterMigrateHeader(string sourceNodeId, bool replace, bool isMa
             tcsQueue.Enqueue(currTcsIterationTask);
             curr = offset;
             this.isMainStore = isMainStore;
+            this.ist = IncrementalSendType.MIGRATE;
             var storeType = isMainStore ? MAIN_STORE : OBJECT_STORE;
             var replaceOption = replace ? T : F;
 

libs/client/ClientSession/GarnetClientSessionReplicationExtensions.cs

@@ -19,6 +19,8 @@ public sealed unsafe partial class GarnetClientSession : IServerHook, IMessageCo
         static ReadOnlySpan<byte> send_ckpt_metadata => "SEND_CKPT_METADATA"u8;
         static ReadOnlySpan<byte> send_ckpt_file_segment => "SEND_CKPT_FILE_SEGMENT"u8;
         static ReadOnlySpan<byte> begin_replica_recover => "BEGIN_REPLICA_RECOVER"u8;
+        static ReadOnlySpan<byte> attach_sync => "ATTACH_SYNC"u8;
+        static ReadOnlySpan<byte> sync => "SYNC"u8;
 
         /// <summary>
         /// Initiate checkpoint retrieval from replica by sending replica checkpoint information and AOF address range
@@ -352,5 +354,118 @@ public Task<string> ExecuteBeginReplicaRecover(bool sendStoreCheckpoint, bool se
             Interlocked.Increment(ref numCommands);
             return tcs.Task;
         }
+
+        /// <summary>
+        /// Initiate attach from replica
+        /// </summary>
+        /// <param name="syncMetadata"></param>
+        /// <returns></returns>
+        public Task<string> ExecuteAttachSync(byte[] syncMetadata)
+        {
+            var tcs = new TaskCompletionSource<string>(TaskCreationOptions.RunContinuationsAsynchronously);
+            tcsQueue.Enqueue(tcs);
+            byte* curr = offset;
+            int arraySize = 3;
+
+            while (!RespWriteUtils.TryWriteArrayLength(arraySize, ref curr, end))
+            {
+                Flush();
+                curr = offset;
+            }
+            offset = curr;
+
+            //1
+            while (!RespWriteUtils.TryWriteDirect(CLUSTER, ref curr, end))
+            {
+                Flush();
+                curr = offset;
+            }
+            offset = curr;
+
+            //2
+            while (!RespWriteUtils.TryWriteBulkString(attach_sync, ref curr, end))
+            {
+                Flush();
+                curr = offset;
+            }
+            offset = curr;
+
+            //3
+            while (!RespWriteUtils.TryWriteBulkString(syncMetadata, ref curr, end))
+            {
+                Flush();
+                curr = offset;
+            }
+            offset = curr;
+
+            Flush();
+            Interlocked.Increment(ref numCommands);
+            return tcs.Task;
+        }
+
+        /// <summary>
+        /// Set CLUSTER SYNC header info
+        /// </summary>
+        /// <param name="sourceNodeId"></param>
+        /// <param name="isMainStore"></param>
+        public void SetClusterSyncHeader(string sourceNodeId, bool isMainStore)
+        {
+            currTcsIterationTask = new TaskCompletionSource<string>(TaskCreationOptions.RunContinuationsAsynchronously);
+            tcsQueue.Enqueue(currTcsIterationTask);
+            curr = offset;
+            this.isMainStore = isMainStore;
+            this.ist = IncrementalSendType.SYNC;
+            var storeType = isMainStore ? MAIN_STORE : OBJECT_STORE;
+
+            var arraySize = 5;
+            while (!RespWriteUtils.TryWriteArrayLength(arraySize, ref curr, end))
+            {
+                Flush();
+                curr = offset;
+            }
+            offset = curr;
+
+            // 1
+            while (!RespWriteUtils.TryWriteDirect(CLUSTER, ref curr, end))
+            {
+                Flush();
+                curr = offset;
+            }
+            offset = curr;
+
+            // 2
+            while (!RespWriteUtils.TryWriteBulkString(sync, ref curr, end))
+            {
+                Flush();
+                curr = offset;
+            }
+            offset = curr;
+
+            // 3
+            while (!RespWriteUtils.TryWriteAsciiBulkString(sourceNodeId, ref curr, end))
+            {
+                Flush();
+                curr = offset;
+            }
+            offset = curr;
+
+            // 4
+            while (!RespWriteUtils.TryWriteBulkString(storeType, ref curr, end))
+            {
+                Flush();
+                curr = offset;
+            }
+            offset = curr;
+
+            // 5
+            // Reserve space for the bulk string header + final newline
+            while (ExtraSpace + 2 > (int)(end - curr))
+            {
+                Flush();
+                curr = offset;
+            }
+            head = curr;
+            curr += ExtraSpace;
+        }
     }
 }

libs/cluster/Server/ClusterProvider.cs

@@ -179,7 +179,7 @@ public void SafeTruncateAOF(StoreType storeType, bool full, long CheckpointCover
                 _ = replicationManager.SafeTruncateAof(CheckpointCoveredAofAddress);
             else
             {
-                if (serverOptions.MainMemoryReplication)
+                if (serverOptions.FastAofTruncate)
                     storeWrapper.appendOnlyFile?.UnsafeShiftBeginAddress(CheckpointCoveredAofAddress, truncateLog: true);
                 else
                 {

libs/cluster/Server/Replication/CheckpointEntry.cs

@@ -118,6 +118,7 @@ public byte[] ToByteArray()
 
         public static CheckpointEntry FromByteArray(byte[] serialized)
         {
+            if (serialized.Length == 0) return null;
             var ms = new MemoryStream(serialized);
             var reader = new BinaryReader(ms);
             var cEntry = new CheckpointEntry

libs/cluster/Server/Replication/PrimaryOps/AofSyncTaskInfo.cs

@@ -5,7 +5,6 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Garnet.client;
-using Garnet.common;
 using Microsoft.Extensions.Logging;
 using Tsavorite.core;
 
@@ -24,11 +23,6 @@ internal sealed class AofSyncTaskInfo : IBulkLogEntryConsumer, IDisposable
         readonly long startAddress;
         public long previousAddress;
 
-        /// <summary>
-        /// Used to mark if syncing is in progress
-        /// </summary>
-        SingleWriterMultiReaderLock aofSyncInProgress;
-
         /// <summary>
         /// Check if client connection is healthy
         /// </summary>
@@ -69,11 +63,6 @@ public void Dispose()
 
             // Finally, dispose the cts
             cts?.Dispose();
-
-            // Dispose only if AOF sync has not started
-            // otherwise sync task will dispose the client
-            if (aofSyncInProgress.TryWriteLock())
-                garnetClient?.Dispose();
         }
 
         public unsafe void Consume(byte* payloadPtr, int payloadLength, long currentAddress, long nextAddress, bool isProtected)
@@ -108,16 +97,8 @@ public async Task ReplicaSyncTask()
         {
             logger?.LogInformation("Starting ReplicationManager.ReplicaSyncTask for remote node {remoteNodeId} starting from address {address}", remoteNodeId, startAddress);
 
-            var failedToStart = false;
             try
             {
-                if (!aofSyncInProgress.TryWriteLock())
-                {
-                    logger?.LogWarning("{method} AOF sync for {remoteNodeId} failed to start", nameof(ReplicaSyncTask), remoteNodeId);
-                    failedToStart = true;
-                    return;
-                }
-
                 if (!IsConnected) garnetClient.Connect();
 
                 iter = clusterProvider.storeWrapper.appendOnlyFile.ScanSingle(startAddress, long.MaxValue, scanUncommitted: true, recover: false, logger: logger);
@@ -134,7 +115,7 @@ public async Task ReplicaSyncTask()
             }
             finally
             {
-                if (!failedToStart) garnetClient.Dispose();
+                garnetClient.Dispose();
                 var (address, port) = clusterProvider.clusterManager.CurrentConfig.GetWorkerAddressFromNodeId(remoteNodeId);
                 logger?.LogWarning("AofSync task terminated; client disposed {remoteNodeId} {address} {port} {currentAddress}", remoteNodeId, address, port, previousAddress);
 

libs/cluster/Server/Replication/PrimaryOps/AofTaskStore.cs

@@ -40,7 +40,7 @@ public AofTaskStore(ClusterProvider clusterProvider, int initialSize = 1, ILogge
                 logPageSizeBits = clusterProvider.storeWrapper.appendOnlyFile.UnsafeGetLogPageSizeBits();
                 int logPageSize = 1 << logPageSizeBits;
                 logPageSizeMask = logPageSize - 1;
-                if (clusterProvider.serverOptions.MainMemoryReplication)
+                if (clusterProvider.serverOptions.FastAofTruncate)
                     clusterProvider.storeWrapper.appendOnlyFile.SafeTailShiftCallback = SafeTailShiftCallback;
                 TruncateLagAddress = clusterProvider.storeWrapper.appendOnlyFile.UnsafeGetReadOnlyAddressLagOffset() - 2 * logPageSize;
             }
@@ -162,7 +162,7 @@ public bool TryAddReplicationTask(string remoteNodeId, long startAddress, out Ao
 
                 // Possible AOF data loss: { using null AOF device } OR { main memory replication AND no on-demand checkpoints }
                 bool possibleAofDataLoss = clusterProvider.serverOptions.UseAofNullDevice ||
-                    (clusterProvider.serverOptions.MainMemoryReplication && !clusterProvider.serverOptions.OnDemandCheckpoint);
+                    (clusterProvider.serverOptions.FastAofTruncate && !clusterProvider.serverOptions.OnDemandCheckpoint);
 
                 // Fail adding the task if truncation has happened, and we are not in possibleAofDataLoss mode
                 if (startAddress < TruncatedUntil && !possibleAofDataLoss)
@@ -217,6 +217,114 @@ public bool TryAddReplicationTask(string remoteNodeId, long startAddress, out Ao
             return success;
         }
 
+        public bool TryAddReplicationTasks(ReplicaSyncSession[] replicaSyncSessions, long startAddress)
+        {
+            var current = clusterProvider.clusterManager.CurrentConfig;
+            var success = true;
+            if (startAddress == 0) startAddress = ReplicationManager.kFirstValidAofAddress;
+
+            // First iterate through all sync sessions and add an AOF sync task
+            // All tasks will be
+            foreach (var rss in replicaSyncSessions)
+            {
+                if (rss == null) continue;
+                var replicaNodeId = rss.replicaSyncMetadata.originNodeId;
+                var (address, port) = current.GetWorkerAddressFromNodeId(replicaNodeId);
+
+                try
+                {
+                    rss.AddAofSyncTask(new AofSyncTaskInfo(
+                        clusterProvider,
+                        this,
+                        current.LocalNodeId,
+                        replicaNodeId,
+                        new GarnetClientSession(
+                            new IPEndPoint(IPAddress.Parse(address), port),
+                            clusterProvider.replicationManager.GetAofSyncNetworkBufferSettings,
+                            clusterProvider.replicationManager.GetNetworkPool,
+                            tlsOptions: clusterProvider.serverOptions.TlsOptions?.TlsClientOptions,
+                            authUsername: clusterProvider.ClusterUsername,
+                            authPassword: clusterProvider.ClusterPassword,
+                            logger: logger),
+                        startAddress,
+                        logger));
+                }
+                catch (Exception ex)
+                {
+                    logger?.LogWarning(ex, "{method} creating AOF sync task for {replicaNodeId} failed", nameof(TryAddReplicationTasks), replicaNodeId);
+                    return false;
+                }
+            }
+
+            _lock.WriteLock();
+            try
+            {
+                if (_disposed) return false;
+
+                // Fail adding the task if truncation has happened
+                if (startAddress < TruncatedUntil)
+                {
+                    logger?.LogWarning("{method} failed to add tasks for AOF sync {startAddress} {truncatedUntil}", nameof(TryAddReplicationTasks), startAddress, TruncatedUntil);
+                    return false;
+                }
+
+                foreach (var rss in replicaSyncSessions)
+                {
+                    if (rss == null) continue;
+
+                    var added = false;
+                    // Find if AOF sync task already exists
+                    for (var i = 0; i < numTasks; i++)
+                    {
+                        var t = tasks[i];
+                        Debug.Assert(t != null);
+                        if (t.remoteNodeId == rss.replicaNodeId)
+                        {
+                            tasks[i] = rss.AofSyncTask;
+                            t.Dispose();
+                            added = true;
+                            break;
+                        }
+                    }
+
+                    if (added) continue;
+
+                    // If AOF sync task did not exist and was not added we added below
+                    // Check if array can hold a new AOF sync task
+                    if (numTasks == tasks.Length)
+                    {
+                        var old_tasks = tasks;
+                        var _tasks = new AofSyncTaskInfo[tasks.Length * 2];
+                        Array.Copy(tasks, _tasks, tasks.Length);
+                        tasks = _tasks;
+                        Array.Clear(old_tasks);
+                    }
+                    // Add new AOF sync task
+                    tasks[numTasks++] = rss.AofSyncTask;
+                }
+
+                success = true;
+            }
+            finally
+            {
+                _lock.WriteUnlock();
+
+                if (!success)
+                {
+                    foreach (var rss in replicaSyncSessions)
+                    {
+                        if (rss == null) continue;
+                        if (rss.AofSyncTask != null)
+                        {
+                            rss.AofSyncTask.Dispose();
+                        }
+                    }
+                }
+            }
+
+            return true;
+        }
+
         public bool TryRemove(AofSyncTaskInfo aofSyncTask)
         {
             // Lock addition of new tasks
@@ -288,7 +396,7 @@ public long SafeTruncateAof(long CheckpointCoveredAofAddress = long.MaxValue)
 
             if (TruncatedUntil > 0 && TruncatedUntil < long.MaxValue)
             {
-                if (clusterProvider.serverOptions.MainMemoryReplication)
+                if (clusterProvider.serverOptions.FastAofTruncate)
                 {
                     clusterProvider.storeWrapper.appendOnlyFile?.UnsafeShiftBeginAddress(TruncatedUntil, snapToPageStart: true, truncateLog: true);
                 }