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: Masahiko Sawada <sawada.mshk@gmail.com>, Mithun Cy <mithun.cy@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-01-31T08:41:56Z
Lists: pgsql-hackers 
On Thu, Jan 31, 2019 at 6:41 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Wed, Jan 30, 2019 at 10:41 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
> > The modified page.sql test could fail if the block size is more than
> > 8kB?
>
> That's right, but I don't think current regression tests will work for
> block size greater than 8KB.  I have tried with 16 and 32 as block
> size, there were few failures on the head itself.
>
> > 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.
> >
>
> Yeah, I am not sure either.  I think as this is an existing test, we
> should not try to change it too much.  However, if both you and John
> feel it is better to change, we can go with that.

I have an idea -- instead of adding a bunch of records and hoping that
the relation size and free space is consistent across platforms, how
about we revert to the original test input, and add a BRIN index? That
should have a FSM even with one record.

-- 
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