Horton

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

John Naylor <john.naylor@enterprisedb.com>

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From: John Naylor <john.naylor@enterprisedb.com>
To: Dilip Kumar <dilipbalaut@gmail.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, 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: 2023-01-26T07:08:52Z
Lists: pgsql-hackers 
On Tue, Jan 24, 2023 at 1:17 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Mon, Jan 23, 2023 at 6:00 PM John Naylor
> <john.naylor@enterprisedb.com> wrote:
> >
> > Attached is a rebase to fix conflicts from recent commits.
>
> I have reviewed v22-0022* patch and I have some comments.
>
> 1.
> >It also changes to the column names max_dead_tuples and num_dead_tuples
and to
> >show the progress information in bytes.
>
> I think this statement needs to be rephrased.

Could you be more specific?

> 3.
>
> We are changing the min value of 'maintenance_work_mem' to 2MB. Should
> we do the same for the 'autovacuum_work_mem'?

Yes, we should change that, too. We've discussed previously that
autovacuum_work_mem is possibly rendered unnecessary by this work, but we
agreed that that should be a separate thread. And needs additional testing
to verify.

I agree with your other comments.

--
John Naylor
EDB: http://www.enterprisedb.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