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: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-05-03T08:44:53Z
Lists: pgsql-hackers 
On Fri, May 3, 2019 at 11:43 AM John Naylor <john.naylor@2ndquadrant.com> wrote:
> On Thu, May 2, 2019 at 4:57 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > On Thu, May 2, 2019 at 12:39 PM John Naylor <john.naylor@2ndquadrant.com> wrote:
> > >
> > Can you please test/review?
>
> There isn't enough time. But since I already wrote some debugging
> calls earlier (attached), I gave it a brief spin, I found this patch
> isn't as careful as HEAD making sure we don't try the same block twice
> in a row. If you insert enough tuples into an empty table such that we
> need to extend, you get something like this:
>
> DEBUG:  Not enough space on block 0
> DEBUG:  Now trying block 0
> DEBUG:  Not enough space on block 0
> DEBUG:  Updating local map for block 0
>
> At this point, I'm sorry to say, but I'm in favor of reverting.
>

Fair enough.  I think we have tried to come up with a patch for an
alternative approach, but it needs time.  I will revert this tomorrow.

-- 
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.