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: Alvaro Herrera <alvherre@2ndquadrant.com>, Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-05-01T05:19:14Z
Lists: pgsql-hackers 
On Wed, May 1, 2019 at 11:43 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Tue, Apr 30, 2019 at 7:52 PM Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> > but that seems correct.
> > Sounds better than keeping outdated entries indicating no-space-available.
>
> Agreed, but as mentioned in one of the above emails, I am also bit
> scared that it should not lead to many invalidation messages for small
> relations, so may be we should send the invalidation message only when
> the entire page is empty.

One way would be to send the inval if the new free space is greater
than some percentage of BLCKSZ.

-- 
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.