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Re: AIO writes vs hint bits vs checksums

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Noah Misch <noah@leadboat.com>, pgsql-hackers@postgresql.org, Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@gmail.com>
Date: 2025-08-13T19:38:14Z
Lists: pgsql-hackers 
Hi,

On 2024-10-30 12:45:27 -0400, Andres Freund wrote:
> On 2024-10-30 13:29:01 +0200, Heikki Linnakangas wrote:
> > On 30/10/2024 04:21, Andres Freund wrote:
> > > Attached is a, unfortunately long, series of patches implementing what I
> > > described upthread.
> > 
> > Review of the preparatory patches:
> > 
> > > 0001 Add very basic test for kill_prior_tuples
> > > 
> > >      We currently don't exercise this patch for gist and hash, which seems
> > >      somewhat criminal.
> > 
> > Interesting to use the isolationtester for this. There's just one session,
> > so you're just using it to define reusable steps with handy names.
> 
> Yea. I had started out writing it as a pg_regress style test and it quickly got very
> hard to understand.
> 
> 
> > I'm fine with that, but please add a comment to explain it.
> 
> Makes sense.
> 
> 
> > I wonder if it'd be more straightforward to make it a regular pg_regress
> > test though. There would be some repetition, but would it be so bad?
> 
> I found it to be quite bad. If testing just one AM it's ok-ish, but once you
> test 2-3 it gets very long and repetitive. I guess we could use functions or
> such to make it a bit less painful - but that point, is it actually simpler?
> 
> 
> > You forgot to add the new test to 'isolation_schedule'.
> 
> Oops.
> 
> > typos:
> >  "inex" -> "index"
> >  "does something approximately reasonble" -> "do something approximately
> > reasonable"
> 
> Oops^2.

Pushed the test with these changes.

Greetings,

Andres Freund

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Require share-exclusive lock to set hint bits and to flush

  2. heapam: Move logic to handle HEAP_MOVED into a helper function

  3. Add very basic test for kill_prior_tuples

  4. aio: Add README.md explaining higher level design

  5. heapam: Only set tuple's block once per page in pagemode

  6. bufmgr: Use AIO in StartReadBuffers()

  7. bufmgr: Implement AIO read support

  8. aio: Implement support for reads in smgr/md/fd

  9. aio: Add io_method=io_uring

  10. aio: Add io_method=worker

  11. aio: Infrastructure for io_method=worker

  12. aio: Add core asynchronous I/O infrastructure

  13. bufmgr: Make it easier to change number of buffer state bits