- Staging buffer is flushed every 500ms. In cases where the result
records are slowly generated (e.g. when a where condition
matches very few records), this change causes the server to send
results even though the staging buffer is not full.
- Refactor messageWriter code to use simpler channel based
co-ordination instead of atomic variables.
Batching records into a single SQL Select message in the response
leads to significant speed up as the message header overhead is made
negligible.
This change leads to a speed up of 3-5x for queries that select many
small records.
