Horton

Re: Adding skip scan (including MDAM style range skip scan) to nbtree

Alena Rybakina <a.rybakina@postgrespro.ru>

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From: Alena Rybakina <a.rybakina@postgrespro.ru>
To: Matthias van de Meent <boekewurm+postgres@gmail.com>, Peter Geoghegan <pg@bowt.ie>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Masahiro Ikeda <ikedamsh@oss.nttdata.com>, Tomas Vondra <tomas@vondra.me>, Masahiro.Ikeda@nttdata.com, pgsql-hackers@lists.postgresql.org, Masao.Fujii@nttdata.com
Date: 2025-04-01T17:31:59Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. nbtree: Always set skipScan flag on rescan.

  2. meson: Build numeric.c with -ftree-vectorize.

  3. Fix "variable not found in subplan target lists" in semijoin de-duplication.

  4. Revert "nbtree: Remove useless row compare arg."

  5. nbtree: Remove useless row compare arg.

  6. Prevent premature nbtree array advancement.

  7. nbtree: tighten up array recheck rules.

  8. Avoid treating nonrequired nbtree keys as required.

  9. Adjust overstrong nbtree skip array assertion.

  10. Make NULL tuple values always advance skip arrays.

  11. Avoid extra index searches through preprocessing.

  12. Improve nbtree skip scan primitive scan scheduling.

  13. Further optimize nbtree search scan key comparisons.

  14. Add nbtree skip scan optimization.

  15. Improve nbtree array primitive scan scheduling.

  16. nbtree: Make BTMaxItemSize into object-like macro.

  17. Show index search count in EXPLAIN ANALYZE, take 2.

  18. Make parallel nbtree index scans use an LWLock.

  19. Show index search count in EXPLAIN ANALYZE.

  20. Avoid nbtree parallel scan currPos confusion.

  21. nbtree: Remove useless 'strat' local variable.

  22. Normalize nbtree truncated high key array behavior.

  23. Refactor handling of nbtree array redundancies.

  24. Fix nbtree pgstats accounting with parallel scans.

  25. Avoid parallel nbtree index scan hangs with SAOPs.

  26. Show Parallel Bitmap Heap Scan worker stats in EXPLAIN ANALYZE

  27. Enhance nbtree ScalarArrayOp execution.

  28. Skip checking of scan keys required for directional scan in B-tree

  29. Instead of using a numberOfRequiredKeys count to distinguish required

On 01.04.2025 17:39, Matthias van de Meent wrote:
> On Fri, 28 Mar 2025 at 22:59, Peter Geoghegan<pg@bowt.ie>  wrote:
>> On Tue, Mar 25, 2025 at 7:45 PM Peter Geoghegan<pg@bowt.ie>  wrote:
>>> Attached is v31, which has a much-improved _bt_skip_ikeyprefix (which
>>> I've once again renamed, this time to _bt_set_startikey).
>> Attached is v32
>> +static bool _bt_s**parray_shrink
> I'd like to understand the "shrink" here, as it's not entirely clear to me.
> The functions are exclusively called through dispatch in
> _bt_compare_array_scankey_args, and I'd expected that naming to be
> extended to these functions.
I understood _bt_skiparray_shrink() as the function that refines the 
range of values that a skip array will consider,
by interpreting existing scalar inequality conditions and applying them 
to limit the bounds of the skip scan.
I understood "shrink" to mean narrowing the range of values that the 
skip array will consider during the index scan.

-- 
Regards,
Alena Rybakina
Postgres Professional