Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: John Naylor <jcnaylor@gmail.com>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-10-07T15:41:20Z
Lists: pgsql-hackers 
John Naylor <jcnaylor@gmail.com> writes:
> On 10/6/18, Thomas Munro <thomas.munro@enterprisedb.com> wrote:
>> On Sat, Oct 6, 2018 at 7:47 AM John Naylor <jcnaylor@gmail.com> wrote:
>>> A while back, Robert Haas noticed that the space taken up by very
>>> small tables is dominated by the FSM [1]. Tom suggested that we could
>>> prevent creation of the FSM until the heap has reached a certain
>>> threshold size [2]. Attached is a WIP patch to implement that.

BTW, don't we need a similar hack for visibility maps?

			regards, tom lane

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