Horton

Improve performance of SendRowDescriptionMessage.

Andres Freund <andres@anarazel.de>

View on postgr.es
Commit: 4c119fbcd49ba882791c7b99a1e934b985468e9f
Author: Andres Freund <andres@anarazel.de>
Date: 2017-10-12T00:23:23Z
Releases: 11.0 
Improve performance of SendRowDescriptionMessage.

There's three categories of changes leading to better performance:
- Splitting the per-attribute part of SendRowDescriptionMessage into a
  v2 and a v3 version allows avoiding branches for every attribute.
- Preallocating the size of the buffer to be big enough for all
  attributes and then using pq_write* avoids unnecessary buffer
  size checks & resizing.
- Reusing a persistently allocated StringInfo for all
  SendRowDescriptionMessage() invocations avoids repeated allocations
  & reallocations.

Author: Andres Freund
Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de

Files

PathChange+/−
src/backend/access/common/printtup.c modified +108 −38
src/backend/tcop/postgres.c modified +28 −7
src/include/access/printtup.h modified +2 −2

Discussion