Horton

Re: WIP: Avoid creation of the free space map for small tables

Petr Jelinek <petr.jelinek@2ndquadrant.com>

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From: Petr Jelinek <petr.jelinek@2ndquadrant.com>
To: Alvaro Herrera <alvherre@2ndquadrant.com>, John Naylor <john.naylor@2ndquadrant.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-02-26T15:25:42Z
Lists: pgsql-hackers 
On 26/02/2019 16:20, Alvaro Herrera wrote:
> On 2019-Feb-23, John Naylor wrote:
> 
>> On Fri, Feb 22, 2019 at 3:59 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>>> The reason for not pushing much on making the test pass for
>>> nonstandard block sizes is that when I tried existing tests, there
>>> were already some failures.
>>
>> FWIW, I currently see 8 failures (attached).
> 
> Hmm, not great -- even the strings test fails, which seems to try to handle
> the case explicitly.  I did expect the plan shape ones to fail, but I'm
> surprised about the tablesample one.
> 

The SYSTEM table sampling is basically per-page sampling so it depends
heavily on which rows are on which page.

-- 
  Petr Jelinek                  http://www.2ndQuadrant.com/
  PostgreSQL Development, 24x7 Support, Training & Services

Commits

  1. Improve code comments in b0eaa4c51b.

  2. During pg_upgrade, conditionally skip transfer of FSMs.

  3. Add more tests for FSM.

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

  5. Make FSM test portable.

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

  7. Move page initialization from RelationAddExtraBlocks() to use, take 2.

  8. Avoid creation of the free space map for small heap relations.

  9. In bootstrap mode, don't allow the creation of files if they don't already