Horton

Re: prevent immature WAL streaming

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Andrew Dunstan <andrew@dunslane.net>, "Bossart, Nathan" <bossartn@amazon.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, "andres@anarazel.de" <andres@anarazel.de>, "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: 2021-09-30T16:12:54Z
Lists: pgsql-hackers 
Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> On 2021-Sep-30, Tom Lane wrote:
>> There's still the issue of these tests overriding postgresql.conf
>> entries made by init(), but maybe we can live with that?

> I vote to at least have has_archiving=>1 set wal_level=replica, and
> potentially max_wal_senders=2 too (allows pg_basebackup).

I think this requires a bit more investigation.  I looked quickly
through the pre-existing tests that set has_archiving=>1, and every
single one of them also sets allows_streaming=>1, which no doubt
explains why this issue hasn't come up before.  So now I'm wondering
if any of those other tests is setting allows_streaming only because
of this configuration issue.

More to the point, since we've not previously used the combination
of has_archiving without allows_streaming, I wonder exactly how
we want to define it to work.  I'm not really convinced that it
should be defined as "allows basebackup even though replication
is supposed to be off".

Perhaps a compromise could be to invent a third option
"allows_basebackup", so that init() actually knows what's going on?

			regards, tom lane

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