Re: parallel vacuum comments

Masahiko Sawada <sawada.mshk@gmail.com>

From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Peter Geoghegan <pg@bowt.ie>, Andres Freund <andres@anarazel.de>
Date: 2021-12-03T12:33:14Z
Lists: pgsql-hackers
 and

On Fri, Dec 3, 2021 at 6:56 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Fri, Dec 3, 2021 at 2:33 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > On Thu, Dec 2, 2021 at 6:01 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> > >
> > > I've attached updated patches.
> > >
> >
> > I have a few comments on v4-0001.
> >
>
> The new test proposed by v4-0003 is increasing the vacuum_parallel.sql
> timing by more than 10 times. It appears to be taking the highest time
> among all the tests in make check. I think it is because of a large
> amount of data being processed by the test.

Right.

> I think it is good to use
> it for testing of patches during development but won't be a good idea
> to commit. Can we reduce its timings?

On reflection, we already have test cases for:

* a parallel vacuum does bulkdeletion and cleanup
* a parallel vacuum does only cleanup

and the case that the new tests add is that a vacuum does bulkdeletion
twice and cleanup. Given the increasing the regression test time, the
thrid patch might not worth to be added.


Regards,

-- 
Masahiko Sawada
EDB:  https://www.enterprisedb.com/



Commits

  1. Move parallel vacuum code to vacuumparallel.c.

  2. Move index vacuum routines to vacuum.c.

  3. Improve parallel vacuum implementation.

  4. Fix parallel amvacuumcleanup safety bug.

  5. Simplify state managed by VACUUM.