Update SQL Server Memory to use the new VECTOR type

extensions/SQLServer/SQLServer/DependencyInjection.cs

@@ -30,14 +30,16 @@ public static IKernelMemoryBuilder WithSqlServerMemoryDb(
     /// Kernel Memory Builder extension method to add SQL Server memory connector.
     /// </summary>
     /// <param name="builder">KM builder instance</param>
-    /// <param name="connString">SQL Server connection string</param>
-    /// <param name="useNativeVectorSearch">Whether to use native vector search or not</param>
+    /// <param name="connectionString">SQL Server connection string</param>
+    /// <param name="useNativeVectorSearch">Whether to use native vector search or not. Currently, the native Vector search is in Early Access Preview (EAP) and is available on Azure SQL Database and Managed Instance only.</param>
+    /// <param name="vectorSize">When <paramref name="useNativeVectorSearch"/> is <see langword="true"/>, it is the vector size used by the VECTOR SQL Server type.</param>
     public static IKernelMemoryBuilder WithSqlServerMemoryDb(
         this IKernelMemoryBuilder builder,
-        string connString,
-        bool useNativeVectorSearch = false)
+        string connectionString,
+        bool useNativeVectorSearch = false,
+        int vectorSize = SqlServerConfig.DefaultVectorSize)
     {
-        builder.Services.AddSqlServerAsMemoryDb(connString, useNativeVectorSearch);
+        builder.Services.AddSqlServerAsMemoryDb(connectionString, useNativeVectorSearch, vectorSize);
         return builder;
     }
 }
@@ -56,6 +58,8 @@ public static IServiceCollection AddSqlServerAsMemoryDb(
         this IServiceCollection services,
         SqlServerConfig config)
     {
+        config.Validate();
+
         return services
             .AddSingleton<SqlServerConfig>(config)
             .AddSingleton<IMemoryDb, SqlServerMemory>();
@@ -65,14 +69,22 @@ public static IServiceCollection AddSqlServerAsMemoryDb(
     /// Inject SQL Server as the default implementation of IMemoryDb
     /// </summary>
     /// <param name="services">Service collection</param>
-    /// <param name="connString">SQL Server connection string</param>
-    /// <param name="useNativeVectorSearch">Whether to use native vector search or not</param>
+    /// <param name="connectionString">SQL Server connection string</param>
+    /// <param name="useNativeVectorSearch">Whether to use native vector search or not. Currently, the native Vector search is in Early Access Preview (EAP) and is available on Azure SQL Database and Managed Instance only.</param>
+    /// <param name="vectorSize">When <paramref name="useNativeVectorSearch"/> is <see langword="true"/>, it is the vector size used by the VECTOR SQL Server type.</param>
     public static IServiceCollection AddSqlServerAsMemoryDb(
         this IServiceCollection services,
-        string connString,
-        bool useNativeVectorSearch = false)
+        string connectionString,
+        bool useNativeVectorSearch = false,
+        int vectorSize = SqlServerConfig.DefaultVectorSize)
     {
-        var config = new SqlServerConfig { ConnectionString = connString, UseNativeVectorSearch = useNativeVectorSearch };
+        var config = new SqlServerConfig
+        {
+            ConnectionString = connectionString,
+            UseNativeVectorSearch = useNativeVectorSearch,
+            VectorSize = vectorSize
+        };
+
         return services.AddSqlServerAsMemoryDb(config);
     }
 }

extensions/SQLServer/SQLServer/QueryProviders/VectorQueryProvider.cs

@@ -90,7 +90,7 @@ public string PrepareGetRecordsListQuery(string index,
         SqlParameterCollection parameters)
     {
         var queryColumns = "[key], [payload], [tags]";
-        if (withEmbeddings) { queryColumns += ", VECTOR_TO_JSON_ARRAY([embedding]) AS [embedding]"; }
+        if (withEmbeddings) { queryColumns += ", CAST([embedding] AS NVARCHAR(MAX)) AS [embedding]"; }
 
         var sql = $"""
                    WITH [filters] AS
@@ -126,19 +126,19 @@ public string PrepareGetSimilarRecordsListQuery(string index,
         if (withEmbedding)
         {
             queryColumns += $"," +
-                            $"VECTOR_TO_JSON_ARRAY({this.GetFullTableName(this._config.MemoryTableName)}.[embedding]) AS [embedding]";
+                            $"CAST({this.GetFullTableName(this._config.MemoryTableName)}.[embedding] AS NVARCHAR(MAX)) AS [embedding]";
         }
 
         var generatedFilters = this.GenerateFilters(index, parameters, filters);
 
         var sql = $"""
                    SELECT TOP (@limit)
                        {queryColumns},
-                       VECTOR_DISTANCE('cosine', JSON_ARRAY_TO_VECTOR(@vector), Embedding) AS [distance]
+                       VECTOR_DISTANCE('cosine', CAST(@vector AS VECTOR({this._config.VectorSize})), Embedding) AS [distance]
                    FROM
                        {this.GetFullTableName(this._config.MemoryTableName)}
                    WHERE
-                       VECTOR_DISTANCE('cosine', JSON_ARRAY_TO_VECTOR(@vector), Embedding) <= @max_distance
+                       VECTOR_DISTANCE('cosine', CAST(@vector AS VECTOR({this._config.VectorSize})), Embedding) <= @max_distance
                        {generatedFilters}
                    ORDER BY [distance] ASC
                    """;
@@ -156,10 +156,10 @@ public string PrepareUpsertRecordsBatchQuery(string index)
                            USING (SELECT @key) as [src]([key])
                            ON {this.GetFullTableName(this._config.MemoryTableName)}.[key] = [src].[key]
                            WHEN MATCHED THEN
-                               UPDATE SET payload=@payload, embedding=JSON_ARRAY_TO_VECTOR(@embedding), tags=@tags
+                               UPDATE SET payload=@payload, embedding=CAST(@embedding AS VECTOR({this._config.VectorSize})), tags=@tags
                            WHEN NOT MATCHED THEN
-                               INSERT ([id], [key], [collection], [payload], [tags], [embedding])
-                               VALUES (NEWID(), @key, @index, @payload, @tags, JSON_ARRAY_TO_VECTOR(@embedding));
+                               INSERT ([key], [collection], [payload], [tags], [embedding])
+                               VALUES (@key, @index, @payload, @tags, CAST(@embedding AS VECTOR({this._config.VectorSize})));
 
                        DELETE FROM [tgt]
                            FROM  {this.GetFullTableName($"{this._config.TagsTableName}_{index}")} AS [tgt]
@@ -211,12 +211,12 @@ PRIMARY KEY ([id])
 
                    IF OBJECT_ID(N'{this.GetFullTableName(this._config.MemoryTableName)}', N'U') IS NULL
                        CREATE TABLE {this.GetFullTableName(this._config.MemoryTableName)}
-                       (   [id] UNIQUEIDENTIFIER NOT NULL,
+                       (   [id] UNIQUEIDENTIFIER NOT NULL DEFAULT NEWSEQUENTIALID(),
                            [key] NVARCHAR(256)  NOT NULL,
                            [collection] NVARCHAR(256) NOT NULL,
                            [payload] NVARCHAR(MAX),
                            [tags] NVARCHAR(MAX),
-                           [embedding] VARBINARY(8000),
+                           [embedding] VECTOR({this._config.VectorSize}),
                            PRIMARY KEY ([id]),
                            FOREIGN KEY ([collection]) REFERENCES {this.GetFullTableName(this._config.MemoryCollectionTableName)}([id]) ON DELETE CASCADE,
                            CONSTRAINT UK_{this._config.MemoryTableName} UNIQUE([collection], [key])

extensions/SQLServer/SQLServer/SqlServerConfig.cs

@@ -30,7 +30,12 @@ public class SqlServerConfig
     /// <summary>
     /// The default schema used by the SQL Server memory store.
     /// </summary>
-    public const string DefaultSchema = "dbo";
+    internal const string DefaultSchema = "dbo";
+
+    /// <summary>
+    /// The default vector size when using the native VECTOR type.
+    /// </summary>
+    internal const int DefaultVectorSize = 1536;
 
     /// <summary>
     /// The connection string to the SQL Server database.
@@ -66,8 +71,38 @@ public class SqlServerConfig
     /// Whether to use native vector search or not.
     /// </summary>
     /// <remarks>
-    /// Currently, Vector Search supports only Azure SQL Database and can handle vectors up to 1998 dimensions.
-    /// See https://devblogs.microsoft.com/azure-sql/announcing-eap-native-vector-support-in-azure-sql-database for more information.
+    /// Currently, the native Vector search is in Early Access Preview (EAP) and is available on Azure SQL Database and Managed Instance only.
+    /// See <a href="https://devblogs.microsoft.com/azure-sql/announcing-eap-native-vector-support-in-azure-sql-database">Announcing EAP for Vector Support in Azure SQL Database</a> for more information.
     /// </remarks>
+    /// <seealso cref="VectorSize"/>
     public bool UseNativeVectorSearch { get; set; } = false;
+
+    /// <summary>
+    /// The vector size when using the native vector search.
+    /// </summary>
+    /// <remarks>
+    /// Currently, the maximum supported vector size is 1998.
+    /// See <a href="https://devblogs.microsoft.com/azure-sql/announcing-eap-native-vector-support-in-azure-sql-database">Announcing EAP for Vector Support in Azure SQL Database</a> for more information.
+    /// </remarks>
+    /// <seealso cref="UseNativeVectorSearch"/>
+    public int VectorSize { get; set; } = DefaultVectorSize;
+
+    /// <summary>
+    /// Verify that the current state is valid.
+    /// </summary>
+    public void Validate()
+    {
+        if (this.UseNativeVectorSearch)
+        {
+            if (this.VectorSize < 0)
+            {
+                throw new ConfigurationException("The vector size must be greater than 0");
+            }
+
+            if (this.VectorSize > 1998)
+            {
+                throw new ConfigurationException("The vector size must be less than or equal to 1998");
+            }
+        }
+    }
 }

extensions/SQLServer/SQLServer/SqlServerMemory.cs

@@ -290,7 +290,7 @@ public async IAsyncEnumerable<MemoryRecord> GetListAsync(
 
             command.Parameters.AddWithValue("@min_relevance_score", minRelevance);
             command.Parameters.AddWithValue("@max_distance", 1 - minRelevance);
-            command.Parameters.AddWithValue("@vector", JsonSerializer.Serialize(embedding.Data.ToArray()));
+            command.Parameters.AddWithValue("@vector", JsonSerializer.Serialize(embedding.Data));
             command.Parameters.AddWithValue("@index", index);
             command.Parameters.AddWithValue("@limit", limit);
 

service/Service/appsettings.json

@@ -622,7 +622,8 @@
         "EmbeddingsTableName": "KMEmbeddings",
         "TagsTableName": "KMMemoriesTags",
         // See https://devblogs.microsoft.com/azure-sql/announcing-eap-native-vector-support-in-azure-sql-database
-        "UseNativeVectorSearch": false
+        "UseNativeVectorSearch": false,
+        "VectorSize": 1536
       }
     }
   }