Horton

Re: prevent immature WAL streaming

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, Andrew Dunstan <andrew@dunslane.net>, "Bossart, Nathan" <bossartn@amazon.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, "masao.fujii@oss.nttdata.com" <masao.fujii@oss.nttdata.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>, "mengjuan.cmj@alibaba-inc.com" <mengjuan.cmj@alibaba-inc.com>, "Jakub.Wartak@tomtom.com" <Jakub.Wartak@tomtom.com>, Ryo Matsumura <matsumura.ryo@fujitsu.com>
Date: 2021-11-10T12:09:03Z
Lists: pgsql-hackers 
On 2021-Nov-09, Tom Lane wrote:

> This is still happening off and on, which makes it look like a
> timing-sensitive problem.  Confirming that, I can make it fail
> every time by adding a long sleep just ahead of where
> 026_overwrite_contrecord.pl captures $initfile.  On reflection
> I think the problem is obvious: if autovacuum does anything
> concurrently with the test's startup portion, it will cause the
> carefully-established WAL insertion point to move into the
> next segment.  I propose to add "autovacuum = off" to the
> test's postmaster configuration.

Ooh, of course.

> Also, I think we want
> 
> -ok($initfile != $endfile, "$initfile differs from $endfile");
> +ok($initfile ne $endfile, "$initfile differs from $endfile");
> 
> The existing coding works as long as all characters of these
> WAL segment names happen to be decimal digits, but ...

Argh!

Thanks for taking care of these issues.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"La conclusión que podemos sacar de esos estudios es que
no podemos sacar ninguna conclusión de ellos" (Tanenbaum)

Commits

  1. Fix determination of broken LSN in OVERWRITTEN_CONTRECORD

  2. Fix instability in 026_overwrite_contrecord.pl test.

  3. Fix typo

  4. Change recently added test code for stability

  5. Remove unstable, unnecessary test; fix typo

  6. Repair two portability oversights of new test

  7. Fix WAL replay in presence of an incomplete record

  8. Document XLOG_INCLUDE_XID a little better

  9. Revert "Avoid creating archive status ".ready" files too early"

  10. Avoid creating archive status ".ready" files too early

  11. Fix scenario where streaming standby gets stuck at a continuation record.

  12. Teach xlogreader to follow timeline switches

  13. Forbid using pg_xlogfile_name() and pg_xlogfile_name_offset() during