Re: Avoid overhead open-close indexes (catalog updates)

Michael Paquier <michael@paquier.xyz>

From: Michael Paquier <michael@paquier.xyz>
To: Ranier Vilela <ranier.vf@gmail.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, pgsql-hackers@postgresql.org
Date: 2022-11-10T08:16:22Z
Lists: pgsql-hackers
On Thu, Sep 01, 2022 at 08:42:15AM -0300, Ranier Vilela wrote:
> Let's wait for the patch to be accepted and committed, so we can try to
> change it.

FWIW, I think that this switch is a good idea for cases where we
potentially update a bunch of tuples, especially based on what
CatalogTupleInsert() tells in its top comment.  Each code path updated
here needs a performance check to see if that's noticeable enough, but
I can get behind the one of CopyStatistics(), at least.

EnumValuesCreate() would matter less as this would require a large set
of values in an enum, but perhaps ORMs would care and that should be
measurable.  update_attstats() should lead to a measurable difference
with a relation that has a bunch of attributes with few tuples.
DefineTSConfiguration() is less of an issue, still fine to change.
AddRoleMems() should be equally measurable with a large DDL.  As a
whole, this looks pretty sane to me and a good idea to move on with.

I still need to check properly the code paths changed here, of
course..
-- 
Michael

Commits

  1. Use multi-inserts for pg_ts_config_map

  2. Use multi-inserts for pg_enum

  3. Avoid some overhead with open and close of catalog indexes

  4. Preserve index data in pg_statistic across REINDEX CONCURRENTLY