Horton

RE: reloption to prevent VACUUM from truncating empty pages at the end of relation

Jamison, Kirk <k.jamison@jp.fujitsu.com>

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From: "Jamison, Kirk" <k.jamison@jp.fujitsu.com>
To: "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, 'Amit Kapila' <amit.kapila16@gmail.com>, Laurenz Albe <laurenz.albe@cybertec.at>, Tom Lane <tgl@sss.pgh.pa.us>, Fujii Masao <masao.fujii@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-02-01T07:01:59Z
Lists: pgsql-hackers

Commits

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  1. Add TRUNCATE parameter to VACUUM.

  2. Add vacuum_truncate reloption.

  3. Allow VACUUM to be run with index cleanup disabled.

On February 1, 2019, Tsunakawa, Takayuki wrote: 

>> As most people seem to agree adding the reloption, here's the patch.  
>> It passes make check, and works like this:

>Sorry, I forgot to include the modified header file.  Revised patch attached.

Thank you for this.
I applied the patch. It builds successfully, and passed the regression tests.
I also tried testing with the parameter when its enabled and disabled,
and it works as intended for CREATE TABLE and ALTER TABLE a SET (shrink_enabled = on/off) and RESET (shrink_enabled).
I have yet to test the performance benchmark.

I wonder if there is a better reloption name for shrink_enabled. (truncate_enabled, vacuum_enabled? Hmm. No?)
On the other hand, shrink_enabled seems to describe well what it's supposed to do when vacuuming tables.
Besides there's a similarly-named autovacuum_enabled option.

I think if most seem to agree to have this solution in place
and to review this further and cover what might be missing,
then shall we register this to next CF?

Regards,
Kirk Jamison