Horton

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

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Fujii Masao <masao.fujii@oss.nttdata.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-07-03T15:16:42Z
Lists: pgsql-hackers 
Nathan Bossart <nathandbossart@gmail.com> writes:
> This sort of thing comes up enough that perhaps we should add a
> better-supported way to deal with GUCs that depend on each other...

Yeah, a GUC check hook that tries to inspect the value of some
other GUC is generally going to create more problems than it
solves; we've learned that the hard way in the past.  We have
your patch to remove one instance of that on the CF queue:

https://www.postgresql.org/message-id/flat/ZnMr2k-Nk5vj7T7H@nathan

But that fix only works because those GUCs are PGC_POSTMASTER
and so we can perform a consistency check on them after GUC setup.

I'm not sure what a more general consistency check mechanism would
look like, but it would have to act at some other point than the
check_hooks do.

			regards, tom lane

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