Horton

Re: Add a GUC check hook to ensure summarize_wal cannot be enabled when wal_level is minimal

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Fujii Masao <masao.fujii@oss.nttdata.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-07-16T16:30:17Z
Lists: pgsql-hackers 
On Tue, Jul 16, 2024 at 12:23:19PM -0400, Robert Haas wrote:
> TBH, I don't want to do that. I think it's too fragile. It's the sort
> of thing that just barely works given the exact behavior of these
> particular GUCs, but it relies on a bunch of subtle assumptions which
> won't be evident to future readers of the code. People will very
> possibly copy this barely-working code into other contexts where it
> doesn't work at all, or they'll think the code implementing this is
> buggy even if it isn't.

Agreed.  If there was really no other option, it would at the very least
need a humongous comment that explained why it worked in this specific case
and is unlikely to work in others.  But it sounds like we have another
choice... 

-- 
nathan

Commits

  1. Do not summarize WAL if generated with wal_level=minimal.

  2. Revert "Auto-tune effective_cache size to be 4x shared buffers"

  3. Un-break ecpg test suite under --disable-integer-datetimes.

  4. Again fix initialization of auto-tuned effective_cache_size.

  5. Code review for auto-tuned effective_cache_size.

  6. Auto-tune effective_cache size to be 4x shared buffers