Horton

Re: Is this a problem in GenericXLogFinish()?

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Alexander Lakhin <exclusion@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Jeff Davis <pgsql@j-davis.com>, Heikki Linnakangas <hlinnaka@iki.fi>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2024-04-05T04:26:29Z
Lists: pgsql-hackers 
On Wed, Feb 07, 2024 at 06:42:21PM +0900, Michael Paquier wrote:
> On Wed, Feb 07, 2024 at 02:08:42PM +0530, Amit Kapila wrote:
> > Thanks for the report and looking into it. Pushed!
> 
> Thanks Amit for the commit and Kuroda-san for the patch!

I have been pinged about this thread and I should have looked a bit
closer, but wait a minute here.

There is still some divergence between the code path of
_hash_freeovflpage() and the replay in hash_xlog_squeeze_page() when
squeezing a page: we do not set the LSN of the write buffer if
(xlrec.ntups <= 0 && xlrec.is_prim_bucket_same_wrt &&
!xlrec.is_prev_bucket_same_wrt) when generating the squeeze record,
but at replay we call PageSetLSN() on the write buffer and mark it
dirty in this case.  Isn't that incorrect?  It seems to me that we
should be able to make the conditional depending on the state of the
xl_hash_squeeze_page record, no?
--
Michael

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.