Query and change feed: Add serialization optimization by using array instead of by item

Microsoft.Azure.Cosmos/src/ChangeFeedProcessor/FeedManagement/RemainingWorkEstimatorCore.cs

@@ -175,9 +175,9 @@ private static IEnumerable<JObject> GetItemsFromResponse(ResponseMessage respons
  return new Collection<JObject>();
  }
 
- return CosmosContainerExtensions.DefaultJsonSerializer.FromFeedResponseStream<JObject>(
- response.Content,
- ResourceType.Document);
+ return CosmosFeedResponseSerializer.FromFeedResponseStream<JObject>(
+ CosmosContainerExtensions.DefaultJsonSerializer,
+ response.Content);
  }
 
  private async Task<long> GetRemainingWorkAsync(DocumentServiceLease existingLease, CancellationToken cancellationToken)

Microsoft.Azure.Cosmos/src/ChangeFeedProcessor/FeedProcessing/FeedProcessorCore.cs

@@ -118,9 +118,9 @@ private Task DispatchChangesAsync(ResponseMessage response, CancellationToken ca
  IEnumerable<T> asFeedResponse;
  try
  {
- asFeedResponse = this.serializerCore.FromFeedResponseStream<T>(
- response.Content,
- Documents.ResourceType.Document);
+ asFeedResponse = CosmosFeedResponseSerializer.FromFeedResponseStream<T>(
+ this.serializerCore,
+ response.Content);
  }
  catch (Exception serializationException)
  {

Microsoft.Azure.Cosmos/src/ChangeFeedProcessor/LeaseManagement/DocumentServiceLeaseContainerCosmos.cs

@@ -58,9 +58,9 @@ private async Task<IReadOnlyList<DocumentServiceLeaseCore>> ListDocumentsAsync(s
  using (ResponseMessage responseMessage = await iterator.ReadNextAsync().ConfigureAwait(false))
  {
  responseMessage.EnsureSuccessStatusCode();
- leases.AddRange(CosmosContainerExtensions.DefaultJsonSerializer.FromFeedResponseStream<DocumentServiceLeaseCore>(
- responseMessage.Content,
- Documents.ResourceType.Document));
+ leases.AddRange(CosmosFeedResponseSerializer.FromFeedResponseStream<DocumentServiceLeaseCore>(
+ CosmosContainerExtensions.DefaultJsonSerializer,
+ responseMessage.Content));
  } 
  }
 

Microsoft.Azure.Cosmos/src/Query/v3Query/ReadFeedResponse.cs

@@ -4,28 +4,21 @@
 namespace Microsoft.Azure.Cosmos
 {
  using System.Collections.Generic;
- using System.IO;
  using System.Net;
- using Microsoft.Azure.Cosmos.CosmosElements;
- using Microsoft.Azure.Cosmos.Json;
- using Microsoft.Azure.Cosmos.Serializer;
 
  internal class ReadFeedResponse<T> : FeedResponse<T>
  {
  protected ReadFeedResponse(
  HttpStatusCode httpStatusCode,
- CosmosArray cosmosArray,
- CosmosSerializerCore serializerCore,
+ IReadOnlyCollection<T> resources,
  Headers responseMessageHeaders,
  CosmosDiagnostics diagnostics)
  {
- this.Count = cosmosArray != null ? cosmosArray.Count : 0;
+ this.Count = resources?.Count ?? 0;
  this.Headers = responseMessageHeaders;
  this.StatusCode = httpStatusCode;
  this.Diagnostics = diagnostics;
- this.Resource = CosmosElementSerializer.GetResources<T>(
- cosmosArray: cosmosArray,
- serializerCore: serializerCore);
+ this.Resource = resources;
  }
 
  public override int Count { get; }
@@ -47,8 +40,7 @@ public override IEnumerator<T> GetEnumerator()
 
  internal static ReadFeedResponse<TInput> CreateResponse<TInput>(
  ResponseMessage responseMessage,
- CosmosSerializerCore serializerCore,
- Documents.ResourceType resourceType)
+ CosmosSerializerCore serializerCore)
  {
  using (responseMessage)
  {
@@ -58,19 +50,13 @@ internal static ReadFeedResponse<TInput> CreateResponse<TInput>(
  responseMessage.EnsureSuccessStatusCode();
  }
 
- CosmosArray cosmosArray = null;
- if (responseMessage.Content != null)
- {
- cosmosArray = CosmosElementSerializer.ToCosmosElements(
- responseMessage.Content,
- resourceType,
- null);
- }
+ IReadOnlyCollection<TInput> resources = CosmosFeedResponseSerializer.FromFeedResponseStream<TInput>(
+ serializerCore,
+ responseMessage.Content);
 
  ReadFeedResponse<TInput> readFeedResponse = new ReadFeedResponse<TInput>(
  httpStatusCode: responseMessage.StatusCode,
- cosmosArray: cosmosArray,
- serializerCore: serializerCore,
+ resources: resources,
  responseMessageHeaders: responseMessage.Headers,
  diagnostics: responseMessage.Diagnostics);
 

Microsoft.Azure.Cosmos/src/Resource/CosmosResponseFactoryCore.cs

@@ -31,17 +31,7 @@ public override FeedResponse<T> CreateChangeFeedUserTypeResponse<T>(
  ResponseMessage responseMessage)
  {
  return this.CreateChangeFeedResponseHelper<T>(
- responseMessage,
- Documents.ResourceType.Document);
- }
-
- public override FeedResponse<T> CreateChangeFeedUserTypeResponse<T>(
- ResponseMessage responseMessage,
- Documents.ResourceType resourceType)
- {
- return this.CreateChangeFeedResponseHelper<T>(
- responseMessage,
- resourceType);
+ responseMessage);
  }
 
  public override FeedResponse<T> CreateQueryFeedUserTypeResponse<T>(
@@ -75,18 +65,15 @@ private FeedResponse<T> CreateQueryFeedResponseHelper<T>(
 
  return ReadFeedResponse<T>.CreateResponse<T>(
  cosmosResponseMessage,
- this.serializerCore,
- resourceType);
+ this.serializerCore);
  }
 
  private FeedResponse<T> CreateChangeFeedResponseHelper<T>(
- ResponseMessage cosmosResponseMessage,
- Documents.ResourceType resourceType)
+ ResponseMessage cosmosResponseMessage)
  {
  return ReadFeedResponse<T>.CreateResponse<T>(
  cosmosResponseMessage,
- this.serializerCore,
- resourceType);
+ this.serializerCore);
  }
 
  public override ItemResponse<T> CreateItemResponse<T>(

Microsoft.Azure.Cosmos/src/Resource/CosmosResponseFactoryInternal.cs

@@ -12,10 +12,6 @@ internal abstract class CosmosResponseFactoryInternal : CosmosResponseFactory
  public abstract FeedResponse<T> CreateChangeFeedUserTypeResponse<T>(
  ResponseMessage responseMessage);
 
- public abstract FeedResponse<T> CreateChangeFeedUserTypeResponse<T>(
- ResponseMessage responseMessage,
- Documents.ResourceType resourceType);
-
  public abstract FeedResponse<T> CreateQueryFeedUserTypeResponse<T>(
  ResponseMessage responseMessage);
 

Microsoft.Azure.Cosmos/src/Serializer/CosmosElementSerializer.cs

@@ -22,30 +22,6 @@ namespace Microsoft.Azure.Cosmos.Serializer
 #endif
  static class CosmosElementSerializer
  {
- /// <summary>
- /// Converts a list of CosmosElements into a memory stream.
- /// </summary>
- /// <param name="stream">The stream response from Azure Cosmos</param>
- /// <param name="resourceType">The resource type</param>
- /// <param name="cosmosSerializationOptions">The custom serialization options. This allows custom serialization types like BSON, JSON, or other formats</param>
- /// <returns>Returns a memory stream of cosmos elements. By default the memory stream will contain JSON.</returns>
- internal static CosmosArray ToCosmosElements(
- Stream stream,
- ResourceType resourceType,
- CosmosSerializationFormatOptions cosmosSerializationOptions = null)
- {
- MemoryStream memoryStream = stream as MemoryStream;
- if (memoryStream == null)
- {
- memoryStream = new MemoryStream();
- stream.CopyTo(memoryStream);
- }
-
- return CosmosElementSerializer.ToCosmosElements(
- memoryStream,
- resourceType,
- cosmosSerializationOptions);
- }
  /// <summary>
  /// Converts a list of CosmosElements into a memory stream.
  /// </summary>
@@ -236,16 +212,10 @@ internal static MemoryStream ToStream(
 
  jsonWriter.WriteObjectEnd();
 
- ReadOnlyMemory<byte> result = jsonWriter.GetResult();
- if (!MemoryMarshal.TryGetArray(result, out ArraySegment<byte> resultAsArray))
- {
- resultAsArray = new ArraySegment<byte>(result.ToArray());
- }
-
- return new MemoryStream(resultAsArray.Array, resultAsArray.Offset, resultAsArray.Count, writable: false, publiclyVisible: true);
+ return GetMemoryStreamFromJsonWriter(jsonWriter);
  }
 
- internal static IEnumerable<T> GetResources<T>(
+ internal static IReadOnlyList<T> GetResources<T>(
  IReadOnlyList<CosmosElement> cosmosArray,
  CosmosSerializerCore serializerCore)
  {
@@ -256,36 +226,35 @@ internal static IEnumerable<T> GetResources<T>(
 
  if (typeof(CosmosElement).IsAssignableFrom(typeof(T)))
  {
- return cosmosArray.Cast<T>();
+ return cosmosArray.Cast<T>().ToList();
  }
 
  return CosmosElementSerializer.GetResourcesHelper<T>(
  cosmosArray,
  serializerCore);
  }
 
- private static IEnumerable<T> GetResourcesHelper<T>(
- IReadOnlyList<CosmosElement> cosmosArray,
- CosmosSerializerCore serializerCore)
+ internal static T[] GetResourcesHelper<T>(
+ IReadOnlyList<CosmosElement> cosmosElements,
+ CosmosSerializerCore serializerCore,
+ CosmosSerializationFormatOptions cosmosSerializationOptions = null)
  {
- List<T> result = new List<T>();
- foreach (CosmosElement element in cosmosArray)
+ using (MemoryStream memoryStream = ElementsToMemoryStream(
+ cosmosElements,
+ cosmosSerializationOptions))
  {
- MemoryStream memory = CosmosElementSerializer.ElementToMemoryStream(element, null);
- result.Add(serializerCore.FromStream<T>(memory));
+ return serializerCore.FromFeedStream<T>(memoryStream);
  }
-
- return result;
  }
 
  /// <summary>
  /// Converts a list of CosmosElements into a memory stream.
  /// </summary>
- /// <param name="cosmosElement">The cosmos elements</param>
+ /// <param name="cosmosElements">The cosmos elements</param>
  /// <param name="cosmosSerializationOptions">The custom serialization options. This allows custom serialization types like BSON, JSON, or other formats</param>
  /// <returns>Returns a memory stream of cosmos elements. By default the memory stream will contain JSON.</returns>
- private static MemoryStream ElementToMemoryStream(
- CosmosElement cosmosElement,
+ internal static MemoryStream ElementsToMemoryStream(
+ IReadOnlyList<CosmosElement> cosmosElements,
  CosmosSerializationFormatOptions cosmosSerializationOptions = null)
  {
  IJsonWriter jsonWriter;
@@ -298,15 +267,32 @@ private static MemoryStream ElementToMemoryStream(
  jsonWriter = JsonWriter.Create(JsonSerializationFormat.Text);
  }
 
- cosmosElement.WriteTo(jsonWriter);
+ jsonWriter.WriteArrayStart();
+
+ foreach (CosmosElement element in cosmosElements)
+ {
+ element.WriteTo(jsonWriter);
+ }
+
+ jsonWriter.WriteArrayEnd();
+
+ return GetMemoryStreamFromJsonWriter(jsonWriter);
+ }
 
+ private static MemoryStream GetMemoryStreamFromJsonWriter(IJsonWriter jsonWriter)
+ {
  ReadOnlyMemory<byte> result = jsonWriter.GetResult();
  if (!MemoryMarshal.TryGetArray(result, out ArraySegment<byte> resultAsArray))
  {
  resultAsArray = new ArraySegment<byte>(result.ToArray());
  }
 
- return new MemoryStream(resultAsArray.Array, resultAsArray.Offset, resultAsArray.Count);
+ return new MemoryStream(
+ buffer: resultAsArray.Array,
+ index: resultAsArray.Offset,
+ count: resultAsArray.Count,
+ writable: false,
+ publiclyVisible: true);
  }
 
  private static string GetRootNodeName(ResourceType resourceType)