Horton

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

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

View thread View on postgr.es
From: John Naylor <john.naylor@2ndquadrant.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-04-18T08:40:06Z
Lists: pgsql-hackers 
On Thu, Apr 18, 2019 at 2:48 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> I respect and will follow whatever will be the consensus after
> discussion.  However, I request you to wait for some time to let the
> discussion conclude.  If we can't get to an
> agreement or one of John or me can't implement what is decided, then
> we can anyway revert it.

Agreed. I suspect the most realistic way to address most of the
objections in a short amount of time would be to:

1. rip out the local map
2. restore hio.c to only checking the last block in the relation if
there is no FSM (and lower the threshold to reduce wasted space)
3. reduce calls to smgr_exists()

Thoughts?

-- 
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.