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: Masahiko Sawada <sawada.mshk@gmail.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: 2023-02-22T09:55:30Z
Lists: pgsql-hackers 
On Wed, Feb 22, 2023 at 3:29 PM Masahiko Sawada <sawada.mshk@gmail.com>
wrote:
>
> On Wed, Feb 22, 2023 at 4:35 PM John Naylor
> <john.naylor@enterprisedb.com> wrote:
> >
> >  I don't think any vacuum calls in regression tests would stress any of
this code very much, so it's not worth carrying the old way forward. I was
thinking of only doing this as a short-time sanity check for testing a
real-world workload.
>
> I guess that It would also be helpful at least until the GA release.
> People will be able to test them easily on their workloads or their
> custom test scenarios.

That doesn't seem useful to me. If we've done enough testing to reassure us
the new way always gives the same answer, the old way is not needed at
commit time. If there is any doubt it will always give the same answer,
then the whole patchset won't be committed.

TPC-C was just an example. It should have testing comparing the old and new
methods. If you have already done that to some degree, that might be
enough. After performance tests, I'll also try some vacuums that use the
comparison patch.

--
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