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perf: copy bitmaps a word at a time in pre_selection_scatter - #25494
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abokhalill wants to merge 1 commit into
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Thank you for opening this pull request! Reviewer note: cargo-semver-checks reported the current version number is not SemVer-compatible with the changes in this pull request (compared against the base branch). Details |
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #25494 +/- ##
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- Coverage 82.37% 82.37% -0.01%
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Files 1138 1138
Lines 433506 433529 +23
Branches 433506 433529 +23
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+ Hits 357102 357107 +5
- Misses 54850 54862 +12
- Partials 21554 21560 +6 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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Slicing the RHS array per selected run clones and drops an Arc on every iteration, and iterating the slice sets one bit per row while both sides are already bit-packed. Borrow the RHS buffers once and copy each run with append_packed_range. Only build a validity bitmap when the RHS has nulls, so a null-free result does not pay a second pass per run. TPC-H SF30 on 24 threads: q6 -8.3%, q12 -4.1%, q19 -2.0%, others within noise.
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@kosiew done. the speedups are actually even more prominent now! |
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Which issue does this PR close?
Rationale for this change
pre_selection_scatterputs the short-circuited RHS result back at full batch length. For each run of selected rows it slices the RHS and appends oneOption<bool>at a time, even though both sides are bit-packed, and everysliceclones and drops anArc.Since #25771,
ANDchains of cheap comparisons no longer reach this function, so TPC-H is unchanged. It still runs forOR, and forANDwith a conjunct that is not cheap.TPC-H SF30
lineitem, 24 threads,l_quantity > K or l_discount > 0.05, by share of rows that reach the RHS:l_quantity < K and l_comment like '%special%'is 1-2% faster. The 22 TPC-H queries are within noise.What changes are included in this PR?
Borrow the RHS buffers once, copy each run with
append_packed_range, and only build a validity bitmap when the RHS has nulls.Are these changes tested?
Yes, by the existing tests, including
test_pre_selection_scatter.Are there any user-facing changes?
No.