Horton

Re: Why does PostgresNode.pm set such a low value of max_wal_senders?

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Noah Misch <noah@leadboat.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Alvaro Herrera <alvherre@2ndquadrant.com>, pgsql-hackers@lists.postgresql.org
Date: 2020-10-01T08:01:50Z
Lists: pgsql-hackers 
On Wed, Sep 30, 2020 at 10:38:59PM -0700, Noah Misch wrote:
> In favor of minimal values, we've had semaphore-starved buildfarm members in
> the past.  Perhaps those days are over, seeing that this commit has not yet
> broken a buildfarm member in that particular way.  Keeping max_wal_senders=10
> seems fine.

Indeed, I am not spotting anything suspicious here.

> No, PostgreSQL commit 54c2ecb changed that.  I recommend an explicit
> max_wal_senders=10 in PostgresNode, which makes it easy to test
> wal_level=minimal:
> 
>   printf '%s\n%s\n%s\n' 'log_statement = all' 'wal_level = minimal' 'max_wal_senders = 0' >/tmp/minimal.conf
>   make check-world TEMP_CONFIG=/tmp/minimal.conf
> 
> thorntail is doing the equivalent, hence the failures.

Ah, thanks, I have missed this piece.  So we really need to have a
value set in this module after all.
--
Michael

Commits

  1. Put back explicit setting of replication values within TAP tests.

  2. Remove obsolete replication settings within TAP tests.

  3. Honor TEMP_CONFIG in TAP suites.

  4. Move some code from RewindTest into PostgresNode