pgsql: Fix pgbench performance issue induced by commit af35fe501. - Mailing list pgsql-committers

From Tom Lane
Subject pgsql: Fix pgbench performance issue induced by commit af35fe501.
Date
Msg-id E1tgTIf-005tNY-5q@gemulon.postgresql.org
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Fix pgbench performance issue induced by commit af35fe501.

Commit af35fe501 caused "pgbench -i" to emit a '\r' character
for each data row loaded (when stderr is a terminal).
That's effectively invisible on-screen, but it causes the
connected terminal program to consume a lot of cycles.
It's even worse if you're connected over ssh, as the data
then has to pass through the ssh tunnel.

Simplest fix is to move the added logic inside the if-tests
that check whether to print a progress line.  We could do
it another way that avoids duplicating these few lines,
but on the whole this seems the most transparent way to
write it.

Like the previous commit, back-patch to all supported versions.

Reported-by: Andres Freund <andres@anarazel.de>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://postgr.es/m/4k4drkh7bcmdezq6zbkhp25mnrzpswqi2o75d5uv2eeg3aq6q7@b7kqdmzzwzgb
Backpatch-through: 13

Branch
------
REL_16_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/21b815f92e82f6aad557d99492b12a912943fdbc

Modified Files
--------------
src/bin/pgbench/pgbench.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)


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