Make checkpointing pluggable (#161)

We make FASTER C# checkpointing use a pluggable user-specified interface (ICheckpointManager) for providing devices such as for index and snapshot and for performing the atomic metadata commit. We refactor the current implementation (currently hard coded to use LocalStorageDevice and C# Streams) as a default and reference implementation.
microsoft · Jul 26, 2019 · c617beb · c617beb
1 parent 132c2b1
commit c617beb
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Showing 14 changed files with 600 additions and 380 deletions.
diff --git a/cs/src/core/Allocator/MallocFixedPageSize.cs b/cs/src/core/Allocator/MallocFixedPageSize.cs
@@ -470,10 +470,11 @@ public void Dispose()
         /// Public facing persistence API
         /// </summary>
         /// <param name="device"></param>
+        /// <param name="start_offset"></param>
         /// <param name="numBytes"></param>
-        public void TakeCheckpoint(IDevice device, out ulong numBytes)
+        public void TakeCheckpoint(IDevice device, ulong start_offset, out ulong numBytes)
         {
-            BeginCheckpoint(device, 0UL, out numBytes);
+            BeginCheckpoint(device, start_offset, out numBytes);
         }
 
         /// <summary>
@@ -563,9 +564,10 @@ public int GetPageSize()
         /// <param name="device"></param>
         /// <param name="buckets"></param>
         /// <param name="numBytes"></param>
-        public void Recover(IDevice device, int buckets, ulong numBytes)
+        /// <param name="offset"></param>
+        public void Recover(IDevice device, ulong offset, int buckets, ulong numBytes)
         {
-            BeginRecovery(device, 0UL, buckets, numBytes, out ulong numBytesRead);
+            BeginRecovery(device, offset, buckets, numBytes, out ulong numBytesRead);
         }
 
         /// <summary>

diff --git a/cs/src/core/Index/Common/CheckpointSettings.cs b/cs/src/core/Index/Common/CheckpointSettings.cs
@@ -2,6 +2,8 @@
 // Licensed under the MIT license.
 
 
+using System;
+
 namespace FASTER.core
 {
     /// <summary>
@@ -27,13 +29,20 @@ public enum CheckpointType
     public class CheckpointSettings
     {
         /// <summary>
-        /// Directory where checkpoints are stored
+        /// Checkpoint manager
         /// </summary>
-        public string CheckpointDir = "";
+        public ICheckpointManager CheckpointManager = null;
 
         /// <summary>
         /// Type of checkpoint
         /// </summary>
         public CheckpointType CheckPointType = CheckpointType.Snapshot;
+
+        /// <summary>
+        /// Use specified directory for storing and retrieving checkpoints
+        /// This is a shortcut to providing the following:
+        ///   CheckpointSettings.CheckpointManager = new LocalCheckpointManager(CheckpointDir)
+        /// </summary>
+        public string CheckpointDir = null;
     }
 }