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b619852086
This commit fixes an oversight introduced in c61a2f5841, 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.edijzczkgd25ek6z@awork3.anarazel.de
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. Copyright and license information can be found in the file COPYRIGHT. General documentation about this version of PostgreSQL can be found at: https://www.postgresql.org/docs/devel/ In particular, information about building PostgreSQL from the source code can be found at: https://www.postgresql.org/docs/devel/installation.html The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.