Horton

Re: [PoC] Improve dead tuple storage for lazy vacuum

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: John Naylor <john.naylor@enterprisedb.com>
Cc: Nathan Bossart <nathandbossart@gmail.com>, Andres Freund <andres@anarazel.de>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Yura Sokolov <y.sokolov@postgrespro.ru>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2023-08-27T12:53:00Z
Lists: pgsql-hackers

Attachments

On Wed, Aug 16, 2023 at 8:04 PM John Naylor
<john.naylor@enterprisedb.com> wrote:
>
>
> On Tue, Aug 15, 2023 at 6:53 PM John Naylor <john.naylor@enterprisedb.com> wrote:
> >
> > On Tue, Aug 15, 2023 at 9:34 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> >
> > > BTW cfbot reported that some regression tests failed due to OOM. I've
> > > attached the patch to fix it.
> >
> > Seems worth doing now rather than later, so added this and squashed most of the rest together.
>
> This segfaults because of a mistake fixing a rebase conflict, so v40 attached.
>

Thank you for updating the patch set.

On Tue, Aug 15, 2023 at 11:33 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> On Mon, Aug 14, 2023 at 8:05 PM John Naylor
> <john.naylor@enterprisedb.com> wrote:
> > Looking at the tidstore tests again after some months, I'm not particularly pleased with the amount of code required for how little it seems to be testing, nor the output when something fails. (I wonder how hard it would be to have SQL functions that add blocks/offsets to the tid store, and emit tuples of tids found in the store.)
>
> It would not be hard to have such SQL functions. I'll try it.

I've updated the regression tests for tidstore so that it uses SQL
functions to add blocks/offsets and dump its contents. The new test
covers the same test coverages but it's executed using SQL functions
instead of executing all tests in one SQL function.

0008 patch fixes a bug in tidstore which I found during this work. We
didn't recreate the radix tree in the same memory context when
TidStoreReset().

Regards,

-- 
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com

Commits

  1. radixtree: Fix SIGSEGV at update of embeddable value to non-embeddable.

  2. Get rid of anonymous struct

  3. Teach radix tree to embed values at runtime

  4. Teach TID store to skip bitmap for small numbers of offsets

  5. Use bump context for TID bitmaps stored by vacuum

  6. Fix alignment of stack variable

  7. Use TidStore for dead tuple TIDs storage during lazy vacuum.

  8. Rethink create and attach APIs of shared TidStore.

  9. Fix inconsistent function prototypes with function definitions.

  10. Fix a calculation in TidStoreCreate().

  11. Fix potential integer handling issue in radixtree.h.

  12. Add TIDStore, to store sets of TIDs (ItemPointerData) efficiently.

  13. Fix link error for test_radixtree module on Windows

  14. Blind attempt to fix ODR violations

  15. Fix incorrect format specifier for int64

  16. Fix redefinition of typedefs

  17. Add template for adaptive radix tree

  18. Fix signedness error in 9f225e992 for gcc

  19. Introduce helper SIMD functions for small byte arrays

  20. Optimize vacuuming of relations with no indexes.

  21. Add bound check before bsearch() for performance

  22. Allocate consecutive blocks during parallel seqscans