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: Andres Freund <andres@anarazel.de>
Cc: Matthias van de Meent <boekewurm+postgres@gmail.com>, Yura Sokolov <y.sokolov@postgrespro.ru>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2022-02-13T03:36:13Z
Lists: pgsql-hackers 
On Sun, Feb 13, 2022 at 11:02 AM Andres Freund <andres@anarazel.de> wrote:
>
> Hi,
>
> On 2022-02-11 13:47:01 +0100, Matthias van de Meent wrote:
> > Today I noticed the inefficiencies of our dead tuple storage once
> > again, and started theorizing about a better storage method; which is
> > when I remembered that this thread exists, and that this thread
> > already has amazing results.
> >
> > Are there any plans to get the results of this thread from PoC to committable?
>
> I'm not currently planning to work on it personally. It'd would be awesome if
> somebody did...

Actually, I'm working on simplifying and improving radix tree
implementation for PG16 dev cycle. From the discussion so far I think
it's better to have a data structure that can be used for
general-purpose and is also good for storing TID, not very specific to
store TID. So I think radix tree would be a potent candidate. I have
done the insertion and search implementation.

Regards,

-- 
Masahiko Sawada
EDB:  https://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