Horton

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

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Fujii Masao <masao.fujii@oss.nttdata.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-07-15T20:03:13Z
Lists: pgsql-hackers 
On Mon, Jul 15, 2024 at 2:47 PM Nathan Bossart <nathandbossart@gmail.com> wrote:
> My understanding is that the correctness of this GUC check hook depends on
> wal_level being a PGC_POSTMASTER GUC.  The check hook would always return
> true during startup, and there'd be an additional cross-check in
> PostmasterMain() that would fail startup if necessary.  After that point,
> we know that wal_level cannot change, so the GUC check hook for
> summarize_wal can depend on wal_level.  If it fails, my expectation would
> be that the server would just ignore that change and continue.

But how do you know that, during startup, the setting for
summarize_wal is processed after the setting for wal_level?

-- 
Robert Haas
EDB: http://www.enterprisedb.com

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