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

John Naylor <jcnaylor@gmail.com>

View thread View on postgr.es

From: John Naylor <jcnaylor@gmail.com>

To: Amit Kapila <amit.kapila16@gmail.com>

Cc: pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2018-12-12T21:48:22Z

Lists: pgsql-hackers

Attachments

remove-bootstrap-case-md.patch (text/x-patch) patch

On 11/24/18, Amit Kapila <amit.kapila16@gmail.com> wrote:
> 4. You have mentioned above that "system catalogs created during
> bootstrap still have a FSM if they have any data." and I can also see
> this behavior, have you investigated this point further?

I found the cause of this. There is some special-case code in md.c to
create any file if it's opened in bootstrap mode. I removed this and a
similar special case (attached), and make check still passes. After
digging through the history, I'm guessing this has been useless code
since about 2001, when certain special catalogs were removed.

-John Naylor

Commits

Improve code comments in b0eaa4c51b.
- 06c8a5090ed9 12.0 landed
During pg_upgrade, conditionally skip transfer of FSMs.
- 13e8643bfc29 12.0 landed
Add more tests for FSM.
- 6f918159a97a 12.0 landed
Doc: Update the documentation for FSM behavior for small tables.
- 29d108cdecbe 12.0 landed
Make FSM test portable.
- 08ecdfe7e5e0 12.0 landed
Avoid creation of the free space map for small heap relations, take 2.
- b0eaa4c51bbf 12.0 landed
Move page initialization from RelationAddExtraBlocks() to use, take 2.
- 0d1fe9f74e36 12.0 cited
Avoid creation of the free space map for small heap relations.
- ac88d2962a96 12.0 landed
In bootstrap mode, don't allow the creation of files if they don't already
- d66e3664b8ba 12.0 landed