Horton

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

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: John Naylor <john.naylor@enterprisedb.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, Nathan Bossart <nathandbossart@gmail.com>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Yura Sokolov <y.sokolov@postgrespro.ru>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2023-02-16T16:44:08Z
Lists: pgsql-hackers 
Hi,

On 2023-02-16 16:22:56 +0700, John Naylor wrote:
> On Thu, Feb 16, 2023 at 10:24 AM Masahiko Sawada <sawada.mshk@gmail.com>
> > Right. TidStore is implemented not only for heap, so loading
> > out-of-order TIDs might be important in the future.
> 
> That's what I was probably thinking about some weeks ago, but I'm having a
> hard time imagining how it would come up, even for something like the
> conveyor-belt concept.

We really ought to replace the tid bitmap used for bitmap heap scans. The
hashtable we use is a pretty awful data structure for it. And that's not
filled in-order, for example.

Greetings,

Andres Freund

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