Horton

Re: Confine vacuum skip logic to lazy_scan_skip

Melanie Plageman <melanieplageman@gmail.com>

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From: Melanie Plageman <melanieplageman@gmail.com>
To: Noah Misch <noah@leadboat.com>
Cc: Thomas Munro <thomas.munro@gmail.com>, vignesh C <vignesh21@gmail.com>, Andres Freund <andres@anarazel.de>, Pg Hackers <pgsql-hackers@postgresql.org>, Heikki Linnakangas <hlinnaka@iki.fi>, Nazir Bilal Yavuz <byavuz81@gmail.com>, Robert Haas <robertmhaas@gmail.com>, "Andrey M. Borodin" <x4mmm@yandex-team.ru>
Date: 2024-07-08T18:16:13Z
Lists: pgsql-hackers 
On Sun, Jul 7, 2024 at 10:49 AM Noah Misch <noah@leadboat.com> wrote:
>
> On Fri, Jun 28, 2024 at 05:36:25PM -0400, Melanie Plageman wrote:
> > I've attached a WIP v11 streaming vacuum patch set here that is
> > rebased over master (by Thomas), so that I could add a CF entry for
> > it. It still has the problem with the extra WAL write and fsync calls
> > investigated by Thomas above. Thomas has some work in progress doing
> > streaming write-behind to alleviate the issues with the buffer access
> > strategy and streaming reads. When he gets a version of that ready to
> > share, he will start a new "Streaming Vacuum" thread.
>
> To avoid reviewing the wrong patch, I'm writing to verify the status here.
> This is Needs Review in the commitfest.  I think one of these two holds:
>
> 1. Needs Review is valid.
> 2. It's actually Waiting on Author.  You're commissioning a review of the
>    future-thread patch, not this one.
>
> If it's (1), given the WIP marking, what is the scope of the review you seek?
> I'm guessing performance is out of scope; what else is in or out of scope?

Ah, you're right. I moved it to "Waiting on Author" as we are waiting
on Thomas' version which has a fix for the extra WAL write/sync
behavior.

Sorry for the "Needs Review" noise!

- Melanie

Commits

  1. Fix explicit valgrind interaction in read_stream.c.

  2. Reduce scope of heap vacuum per_buffer_data

  3. Use streaming read I/O in VACUUM's third phase

  4. Use streaming read I/O in VACUUM's first phase

  5. Convert heap_vac_scan_next_block() boolean parameters to flags

  6. Refactor tidstore.c iterator buffering.

  7. Increase default vacuum_buffer_usage_limit to 2MB.

  8. Remove unneeded vacuum_delay_point from heap_vac_scan_get_next_block

  9. Confine vacuum skip logic to lazy_scan_skip()

  10. Set all_visible_according_to_vm correctly with DISABLE_PAGE_SKIPPING

  11. Tighten up VACUUM's approach to setting VM bits.