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: 2019-01-31T12:52:47Z
Lists: pgsql-hackers 
On Thu, Jan 31, 2019 at 1:43 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > 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.
> >
>
> Why would BRIN index allow having FSM for heap relation?

Oops, I forgot this file is for testing heaps only. That said, we
could possibly put most of the FSM tests such as

SELECT * FROM fsm_page_contents(get_raw_page('test_rel_forks', 'fsm', 0));

into brin.sql since we know a non-empty BRIN index will have a FSM.
And in page.sql we could just have a test that the table has no FSM.

-- 
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