Horton

Re: type cache cleanup improvements

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Pavel Borisov <pashkin.elfe@gmail.com>, Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>, Andrei Lepikhov <lepihov@gmail.com>, jian he <jian.universality@gmail.com>, Artur Zakirov <zaartur@gmail.com>, Alexander Lakhin <exclusion@gmail.com>, Teodor Sigaev <teodor@sigaev.ru>, Pgsql Hackers <pgsql-hackers@postgresql.org>, Aleksander Alekseev <aleksander@timescale.com>, Tom Lane <tgl@sss.pgh.pa.us>, Michael Paquier <michael@paquier.xyz>
Date: 2025-04-29T00:56:12Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Maintain RelIdToTypeIdCacheHash in TypeCacheOpcCallback()

  2. Fix concurrrently in typcache_rel_type_cache.sql

  3. Avoid looping over all type cache entries in TypeCacheRelCallback()

  4. Update header comment for lookup_type_cache()

  5. Revert: Avoid looping over all type cache entries in TypeCacheRelCallback()

  6. Introduce hash_search_with_hash_value() function

  7. Optimize InvalidateAttoptCacheCallback() and TypeCacheTypCallback()

  8. Refactor initial hash lookup in dynahash.c

  9. Rationalize and improve error messages for some jsonpath items

  10. Avoid race in RelationBuildDesc() affecting CREATE INDEX CONCURRENTLY.

  11. Represent Lists as expansible arrays, not chains of cons-cells.

On Mon, Apr 21, 2025 at 04:54:08AM +0300, Alexander Korotkov wrote:
> On Sat, Apr 12, 2025 at 12:43 AM Alexander Korotkov <aekorotkov@gmail.com> wrote:
> > On Fri, Apr 11, 2025 at 11:32 PM Noah Misch <noah@leadboat.com> wrote:
> > > On Tue, Oct 22, 2024 at 08:33:24PM +0300, Alexander Korotkov wrote:
> > > > On Tue, Oct 22, 2024 at 6:10 PM Pavel Borisov <pashkin.elfe@gmail.com> wrote:
> > > > > On Tue, 22 Oct 2024 at 11:34, Alexander Korotkov <aekorotkov@gmail.com> wrote:
> > > > >> I'm going to push this if no objections.
> > >
> > > (This became commit b85a9d0.)
> > >
> > > > +     /* Call delete_rel_type_cache() if we actually cleared something */
> > > > +     if (hadTupDescOrOpclass)
> > > > +             delete_rel_type_cache_if_needed(typentry);
> > >
> > > I think the intent was to maintain the invariant that a RelIdToTypeIdCacheHash
> > > entry exists if and only if certain kinds of data appear in the TypeCacheHash
> > > entry.  However, TypeCacheOpcCallback() clears TCFLAGS_OPERATOR_FLAGS without
> > > maintaining RelIdToTypeIdCacheHash.  Is it right to do that?

> Sorry for the delay.  Generally, your finding is correct.  But, I
> didn't manage to reproduce the situation, where existing code leads to
> real error.  In order to have it, we must have typcache entry without
> TCFLAGS_HAVE_PG_TYPE_DATA and tupDesc, but with some of
> TCFLAGS_OPERATOR_FLAGS.

That makes sense.

> Reseting TCFLAGS_HAVE_PG_TYPE_DATA for a
> composite type doesn't seem to be possible without resetting the rest
> at the same time.
> 
> Nevertheless, I think it would be fragile to leave the current code
> "as is".  If even there is no case of real error (or it's just me
> didn't manage to find it), it could appear after further changes of
> type cache code.  So, the fix is attached.

This change looks appropriate.  Thanks.