Horton

Re: Unhappy about API changes in the no-fsm-for-small-rels patch

John Naylor <john.naylor@2ndquadrant.com>

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From: John Naylor <john.naylor@2ndquadrant.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-05-02T07:09:26Z
Lists: pgsql-hackers 
On Thu, May 2, 2019 at 2:31 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> @@ -776,7 +776,10 @@ fsm_extend(Relation rel, BlockNumber fsm_nblocks)
>   if ((rel->rd_smgr->smgr_fsm_nblocks == 0 ||
>   rel->rd_smgr->smgr_fsm_nblocks == InvalidBlockNumber) &&
>   !smgrexists(rel->rd_smgr, FSM_FORKNUM))
> + {
>   smgrcreate(rel->rd_smgr, FSM_FORKNUM, false);
> + fsm_clear_local_map(rel);
> + }
>
> I think this won't be correct because when we call fsm_extend via
> vacuum the local map won't be already existing, so it won't issue an
> invalidation call.  Isn't it better to directly call
> CacheInvalidateRelcache here to notify other backends that their local
> maps are invalid now?

Yes, you're quite correct.

-- 
John Naylor                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Revert "Avoid the creation of the free space map for small heap relations".

  2. Improve code comments in b0eaa4c51b.

  3. During pg_upgrade, conditionally skip transfer of FSMs.

  4. Add more tests for FSM.

  5. Fix typos in commit 8586bf7ed8.

  6. tableam: introduce table AM infrastructure.

  7. Clear the local map when not used.

  8. Doc: Update the documentation for FSM behavior for small tables.

  9. Make FSM test portable.

  10. Avoid creation of the free space map for small heap relations, take 2.