Horton

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

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: Sawada Masahiko <sawada.mshk@gmail.com>, Mithun Cy <mithun.cy@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-01-31T08:32:01Z
Lists: pgsql-hackers 
On Thu, Jan 31, 2019 at 6:37 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Wed, Jan 30, 2019 at 8:11 PM John Naylor <john.naylor@2ndquadrant.com> wrote:
> >
> > That's probably a good idea to limit risk. I just very basic tests
> > now, and vacuum before every relation size check to make sure any FSM
> > extension (whether desired or not) is invoked. Also, in my last patch
> > I forgot to implement explicit checks of the block number instead of
> > assuming how many rows will fit on a page. I've used a plpgsql code
> > block to do this.
> >
>
> -- Extend table with enough blocks to exceed the FSM threshold
>  -- FSM is created and extended to 3 blocks
>
> The second comment line seems redundant to me, so I have removed that
> and integrated it in the main patch.

FYI, the second comment is still present in v20.

-- 
John Naylor                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, 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