Re: Fwd: Big Performance drop of Exceptions in UDFs between V11.2 and 13.4

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Andrew Dunstan <andrew(at)dunslane(dot)net>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Fwd: Big Performance drop of Exceptions in UDFs between V11.2 and 13.4
Date: 2021-08-27 17:30:07
Message-ID: 845520.1630085407@sss.pgh.pa.us
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Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> First, this apparently only affects build done with NLS. And in fact
> even on release 11 the performance is much better when run on a non-NLS
> build. So there's lots of work to do here.

Wow ... it would not have occurred to me to check that.

Testing that angle using HEAD on Linux (RHEL8), here are times
I see for the OP's slow query:

Non-NLS build, C locale:
Time: 12452.062 ms (00:12.452)

NLS build, en_US.utf8 locale:
Time: 13596.114 ms (00:13.596)

NLS build, after SET lc_messages TO 'es_ES.utf8':
Time: 15190.689 ms (00:15.191)

So there is a cost for translating the error messages on Linux too,
but it's not nearly as awful as on Windows. I wonder if this
boils down to a performance bug in the particular gettext version
you're using?

regards, tom lane

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