Horton

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

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: John Naylor <john.naylor@2ndquadrant.com>, Mithun Cy <mithun.cy@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-01-30T17:11:12Z
Lists: pgsql-hackers 
On Wed, Jan 30, 2019 at 4:33 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Tue, Jan 29, 2019 at 8:12 PM John Naylor <john.naylor@2ndquadrant.com> wrote:
> >
> > On Tue, Jan 29, 2019 at 11:56 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > > You can find this change in attached patch.  Then, I ran the make
> > > check in src/bin/pgbench multiple times using test_conc_insert.sh.
> > > You can vary the number of times the test should run, if you are not
> > > able to reproduce it with this.
> > >
> > > The attached patch (clear_local_map_if_exists_1.patch) atop the main
> > > patch fixes the issue for me.  Kindly verify the same.
> >
> > I got one failure in 50 runs. With the new patch, I didn't get any
> > failures in 300 runs.
> >
>
> Thanks for verification.  I have included it in the attached patch and
> I have also modified the page.sql test to have enough number of pages
> in relation so that FSM will get created irrespective of alignment
> boundaries.  Masahiko San, can you verify if this now works for you?
>

Thank you for updating the patch!

The modified page.sql test could fail if the block size is more than
8kB? We can ensure the number of pages are more than 4 by checking it
and adding more data if no enough but I'm really not sure we should
care the bigger-block size cases. However maybe it's good to check the
number of pages after insertion so that we can break down the issue in
case the test failed again.

Regards,

--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center

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