New+Optional memorydb interface to support batch memories upset (#441)

nuget-package.props

@@ -1,7 +1,7 @@
 <Project>
     <PropertyGroup>
         <!-- Central version prefix - applies to all nuget packages. -->
-        <Version>0.38.0</Version>
+        <Version>0.39.0</Version>
 
         <!-- These are set at the project level-->
         <IsPackable>false</IsPackable>

service/Abstractions/MemoryStorage/IMemoryDb.cs

@@ -39,7 +39,7 @@ Task DeleteIndexAsync(
         CancellationToken cancellationToken = default);
 
     /// <summary>
-    /// Insert/Update a vector + payload, creates the given index if it does not exist.
+    /// Insert/Update a vector + payload.
     /// </summary>
     /// <param name="index">Index/Collection name</param>
     /// <param name="record">Vector + payload to save</param>

service/Abstractions/MemoryStorage/IMemoryDbBatchUpsert.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Collections.Generic;
+using System.Threading;
+
+namespace Microsoft.KernelMemory.MemoryStorage;
+
+/// <summary>
+/// Interface for memory DB adapters supporting batch upsert.
+/// The interface is not mandatory and not implemented by all connectors.
+/// Handlers/Clients should check if the interface is available and leverage it to optimize throughput.
+/// </summary>
+public interface IMemoryDbBatchUpsert
+{
+    /// <summary>
+    /// Insert/Update a list of vectors + payload.
+    /// </summary>
+    /// <param name="index">Index/Collection name</param>
+    /// <param name="records">Vectors + payload to save</param>
+    /// <param name="cancellationToken">Task cancellation token</param>
+    /// <returns>Record IDs</returns>
+    /// <exception cref="IndexNotFound">Error returned if the index where to write doesn't exist</exception>
+    IAsyncEnumerable<string> BatchUpsertAsync(
+        string index,
+        IEnumerable<MemoryRecord> records,
+        CancellationToken cancellationToken = default);
+}