Horton

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

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: John Naylor <john.naylor@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-04-19T09:16:13Z
Lists: pgsql-hackers 
On Fri, Apr 19, 2019 at 1:17 PM John Naylor <john.naylor@2ndquadrant.com> wrote:
> On Fri, Apr 19, 2019 at 10:38 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > I think if we go this route, then
> > we might need to revisit it in the future to optimize it, but maybe
> > that is the best alternative as of now.
>
> It's a much lighter-weight API, which has that much going for it.
> I have a draft implementation, which I can share if it comes to that
> -- it needs some more thought and polish first.
>

I understand that it is lighter-weight API, but OTOH, it will be less
efficient as well.  Also, the consensus seems to be that we should
move this to relcache.

> > I am thinking that we should at least give it a try to move the map to
> > rel cache level to see how easy or difficult it is and also let's wait
> > for a day or two to see if Andres/Tom has to say anything about this
> > or on the response by me above to improve the current patch.
>
> Since we have a definite timeline, I'm okay with that, although I'm
> afraid I'm not quite knowledgeable enough to help much with the
> relcache piece.
>

Okay, I can try to help.  I think you can start by looking at
RelationData members (for ex. see how we cache index's metapage in
rd_amcache) and study a bit about routines in relcache.h.


-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com

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.