Re: Adding skip scan (including MDAM style range skip scan) to nbtree
Peter Geoghegan <pg@bowt.ie>
Commits
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the thread's linked commits as JSON, with link sources.
API reference →
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nbtree: Always set skipScan flag on rescan.
- 454c046094ab 19 (unreleased) landed
- bee763aea13f 18.0 landed
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meson: Build numeric.c with -ftree-vectorize.
- 9016fa7e3bcd 19 (unreleased) cited
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Fix "variable not found in subplan target lists" in semijoin de-duplication.
- b8a1bdc458e3 19 (unreleased) cited
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Revert "nbtree: Remove useless row compare arg."
- dd2ce3792754 18.0 landed
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nbtree: Remove useless row compare arg.
- 54c6ea8c81db 18.0 cited
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Prevent premature nbtree array advancement.
- 5f4d98d4f371 18.0 landed
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nbtree: tighten up array recheck rules.
- 7e25c9363a82 18.0 landed
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Avoid treating nonrequired nbtree keys as required.
- 0f08df406822 18.0 landed
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Adjust overstrong nbtree skip array assertion.
- 9d924dbb3710 18.0 landed
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Make NULL tuple values always advance skip arrays.
- b75fedcab791 18.0 cited
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Avoid extra index searches through preprocessing.
- b3f1a13f22f9 18.0 landed
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Improve nbtree skip scan primitive scan scheduling.
- 21a152b37f36 18.0 landed
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Further optimize nbtree search scan key comparisons.
- 8a510275dd6b 18.0 landed
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Add nbtree skip scan optimization.
- 92fe23d93aa3 18.0 landed
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Improve nbtree array primitive scan scheduling.
- 9a2e2a285a14 18.0 landed
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nbtree: Make BTMaxItemSize into object-like macro.
- 426ea611171d 18.0 landed
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Show index search count in EXPLAIN ANALYZE, take 2.
- 0fbceae841cb 18.0 landed
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Make parallel nbtree index scans use an LWLock.
- 67fc4c9fd7fa 18.0 landed
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Show index search count in EXPLAIN ANALYZE.
- 5ead85fbc811 18.0 landed
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Avoid nbtree parallel scan currPos confusion.
- b5ee4e52026b 18.0 cited
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nbtree: Remove useless 'strat' local variable.
- b6558e4f837e 18.0 landed
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Normalize nbtree truncated high key array behavior.
- 79fa7b3b1a44 18.0 landed
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Refactor handling of nbtree array redundancies.
- b524974106ac 18.0 landed
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Fix nbtree pgstats accounting with parallel scans.
- c00c54a9ac1e 18.0 landed
- fb4f5e58af97 17.0 landed
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Avoid parallel nbtree index scan hangs with SAOPs.
- d8adfc18bebf 18.0 landed
- a24bffc021d9 17.0 landed
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Show Parallel Bitmap Heap Scan worker stats in EXPLAIN ANALYZE
- 5a1e6df3b84c 18.0 cited
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Enhance nbtree ScalarArrayOp execution.
- 5bf748b86bc6 17.0 cited
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Skip checking of scan keys required for directional scan in B-tree
- e0b1ee17dc3a 17.0 cited
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Instead of using a numberOfRequiredKeys count to distinguish required
- 7ccaf13a06b8 8.2.0 cited
On Fri, May 9, 2025 at 12:28 PM Tomas Vondra <tomas@vondra.me> wrote: > Not sure if it matters, but this uses index-only scans, and the pages > are all-visible, so maybe it's not much more expensive. You're still going to have to scan 85 full index pages on your pgbench_accounts.bid index -- that's pretty expensive, even with an index-only scan. Even if there was some kind of really obvious regression in preprocessing (which seems almost impossible), I'd still expect it to be drowned out for queries such as these. > Not sure, I did multiple tests with different queries, and it'd be a bit > strange if this was the only one affected. Not impossible. The only thing that substantially differs between this pgbench_accounts.bid query and traditional pgbench SELECT queries (on pgbench_accounts.aid) is 1.) this query is quite a bit more expensive at execution time, and 2.) that it involves the use of partitioning. I made sure to test pgbench SELECT quite thoroughly -- that certainly wasn't regressed. So it seems very likely to have something to do with partitioning. -- Peter Geoghegan