Re: Implement waiting for wal lsn replay: reloaded

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Alexander Korotkov <aekorotkov(at)gmail(dot)com>
Cc: Xuneng Zhou <xunengzhou(at)gmail(dot)com>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Peter Eisentraut <peter(at)eisentraut(dot)org>, Andres Freund <andres(at)anarazel(dot)de>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Álvaro Herrera <alvherre(at)kurilemu(dot)de>, Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Michael Paquier <michael(at)paquier(dot)xyz>, jian he <jian(dot)universality(at)gmail(dot)com>, Tomas Vondra <tomas(at)vondra(dot)me>, Yura Sokolov <y(dot)sokolov(at)postgrespro(dot)ru>
Subject: Re: Implement waiting for wal lsn replay: reloaded
Date: 2026-04-07 01:52:54
Message-ID: 1957514.1775526774@sss.pgh.pa.us
Views: Whole Thread | Raw Message | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Alexander Korotkov <aekorotkov(at)gmail(dot)com> writes:
> Thank you, I've pushed your version of patchset. I made two minor
> corrections for patch #2: mention default mode value in the header
> comment, and fallback to polling on has_wal_read_bug sparc64+ext4 bug.

I wondered why my buildfarm animals got noticeably slower today.
There seem to be a couple of culprits, but one of them is that
7e8aeb9e4 (Use WAIT FOR LSN) has caused the runtime of pg_rewind's
t/003_extrafiles.pl to go through the roof. On indri's host, that
TAP test took about 3 seconds immediately before that commit, and
about 45 seconds immediately after. (For scale, the core regression
tests take about 10 seconds on this machine.) I see roughly
comparable slowdowns on other machines too.

I have not dug into why, nor do I understand why it seems like
only this one test is affected. In any case, surely this is
unacceptable.

regards, tom lane

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Andres Freund 2026-04-07 01:58:19 Re: Adding REPACK [concurrently]
Previous Message Chao Li 2026-04-07 01:45:42 Re: Eliminating SPI / SQL from some RI triggers - take 3