Improve COPY TO performance when server and client encodings match This commit fixes an oversight introduced in c61a2f58418e, where COPY TO would attempt to do encoding conversions even if the encodings of the client and the server matched for multi-byte encodings. All conversions go through pg_any_to_server() that makes the conversion a no-op when the encodings of the client and the server match, even for multi-byte encodings.
The logic was fine, but setting CopyToStateData->need_transcoding would cause strlen() to be called for nothing for each attribute of all the rows copied, and that was showing high in some profiles (more attributes make that easier to reach). This change improves the runtime of some worst-case COPY TO queries by 15%~ (number present at least here). This is a performance improvement, so no backpatch is done out of caution as this is not a regression. Reported-by: Andres Freund Analyzed-by: Andres Freund Author: Michael Paquier Reviewed-by: Heikki Linnakangas Discussion: https://postgr.es/m/20240206020504.edijzczkgd25e...@awork3.anarazel.de Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/b619852086ed2b5df76631f5678f60d3bebd3745 Modified Files -------------- src/backend/commands/copyto.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
