Deprecation Follow-up Work for v22.0 Code Freeze

[mattlord]

Here's a list of deprecation related follow-up work that has not yet happened and which should be done in v22 before the code freeze:

1. Add session flag for stream execute grpc api #14046 (--grpc-send-session-in-streaming)

   • Backport to v17 (disabled - default) - Done
   • Mark for deprecation in v18 (enabled - default) - Not done
   • Removed in v19 - Not done
   • On main/v22: go/vt/vtgate/grpcvtgateservice/server.go: fs.BoolVar(&sendSessionInStreaming, "grpc-send-session-in-streaming", false, "If set, will send the session as last packet in streaming api to support transactions in streaming")

2. Deprecate old reparent metrics and replace with new ones #16031

   • Remove the deprecated metrics

3. Deprecate old metrics in VTOrc and replace with new ones #15994

   • Remove the deprecated metrics

4. deprecate queryserver-enable-settings-pool flag #16280

   • Remove the deprecated flag

5. Deprecate vttablet metrics QueryCacheXX and rename to QueryPlanCacheXX #16289

   • Remove the deprecated metrics