[Feature Request] Optimizations - gRPC plugin

[finnegancarroll]

Is your feature request related to a problem? Please describe

Please describe the end goal of this project

Tracking some optimizations which are specific (or may be more easily applied) to a gRPC server alternative of the OpenSearch API.

Features

• Pass through optimization
  Initial search and index services deserialize protobuf messages into POJO before handing off to internal client to execute a request on the transport layer. We can potentially optimize this process by passing the client protobuf objects necessary to execute the request directly to the client and further propagating these objects across the transport layer. Delegating deserialization work to the shard level.

• Streaming endpoint alternatives
  Protobuf + gRPC enables the simple transformation of regular indexing/search services into streaming alternatives by separating per-request metadata from bulk response body. Maybe most applicable applied to bulk indexing requests and search responses.

message StreamingSearchResponse {
  oneof response {
    // First message will contain metadata
    SearchMetadata metadata = 1;
    // Subsequent messages will contain individual hits
    SearchHitChunk hit = 2;
  }
}

// Streaming search service definition
service StreamingSearchService {
  // Stream search results as they become available
  rpc StreamingSearch(SearchRequest) returns (stream StreamingSearchResponse) {}
}

Describe the solution you'd like

Experimental benchmarking of potential gRPC optimizations.

Related component

Plugins

Describe alternatives you've considered

No benchmarking.

Additional context

Supporting References

Experimental grpc-transport pr - #16534

Ecosystem meta issue