Horton

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

John Naylor <johncnaylorls@gmail.com>

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From: John Naylor <johncnaylorls@gmail.com>
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>, Nathan Bossart <nathandbossart@gmail.com>, Andres Freund <andres@anarazel.de>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Yura Sokolov <y.sokolov@postgrespro.ru>
Date: 2024-01-10T06:40:40Z
Lists: pgsql-hackers

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On Wed, Jan 10, 2024 at 9:05 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> I've done in 0010 patch in v51 patch set.  Whereas RT_NODE_4 and
> RT_NODE_16 structs declaration needs RT_FANOUT_4_HI and
> RT_FANOUT_16_HI respectively, RT_FANOUT_16_LO and RT_FANOUT_48 need
> RT_NODE_16 and RT_NODE_48 structs declaration. So fanout declarations
> are now spread before and after RT_NODE_XXX struct declaration. It's a
> bit less readable, but I'm not sure of a better way.

They were before and after the *_BASE types, so it's not really worse,
I think. I did notice that RT_SLOT_IDX_LIMIT has been considered
special for a very long time, before we even had size classes, so it's
the same thing but even more far away. I have an idea to introduce
*_MAX macros, allowing to turn RT_SLOT_IDX_LIMIT into
RT_FANOUT_48_MAX, so that everything is in the same spot, and to make
this area more consistent. I also noticed that I'd been assuming that
RT_FANOUT_16_HI fits easily into a DSA size class, but that's only
true on 64-bit, and in any case we don't want to assume it. I've
attached an addendum .txt to demo this idea.

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