Horton

Re: Is this a problem in GenericXLogFinish()?

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Jeff Davis <pgsql@j-davis.com>, pgsql-hackers@postgresql.org
Date: 2023-10-11T12:25:12Z
Lists: pgsql-hackers 
On Wed, Oct 11, 2023 at 7:53 AM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
> > + * Buffer must be pinned and exclusive-locked.  (If caller does not hold
> > + * exclusive lock, then the result may be stale before it's returned.)
> The comment suggests that you don't need to hold an exclusive lock when
> you call this, but there's an assertion that you do.

I don't think the comment suggests that. It would if you only read the
sentence in parentheses. But if you read both of them it seems clear
enough. I guess the parenthetical sentence cloud say "If the caller
did not hold an exclusive lock, then the result might become stale
even before it was returned," basically putting the whole thing in the
subjunctive.

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

Commits

  1. Fix inconsistency with replay of hash squeeze record for clean buffers

  2. Set LSN for wbuf in _hash_freeovflpage() iff wbuf is modified.

  3. Fix an uninitialized access in hash_xlog_squeeze_page().

  4. Use REGBUF_NO_CHANGE at one more place in the hash index.

  5. Assert that buffers are marked dirty before XLogRegisterBuffer().

  6. Fix bug in GenericXLogFinish().

  7. Improve hash index bucket split behavior.