[multistage] Support Hash Functions Gracefully in V2 Optimizer #16296
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ankitsultana
added
multi-stage
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## master #16296 +/- ##
============================================
+ Coverage 62.90% 63.19% +0.29%
+ Complexity 1386 1364 -22
============================================
Files 2867 2966 +99
Lines 163354 171673 +8319
Branches 24952 26296 +1344
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+ Hits 102755 108497 +5742
- Misses 52847 54919 +2072
- Partials 7752 8257 +505
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ankitsultana
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shauryachats
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Jul 8, 2025
...java/org/apache/pinot/query/planner/physical/v2/opt/rules/LeafStageWorkerAssignmentRule.java
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shauryachats
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Jul 8, 2025
itschrispeck
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Jul 8, 2025
shauryachats
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Jul 8, 2025
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Summary
This PR fixes some assumptions in the v2 query optimizer, specifically about hash functions. With this PR, we achieve the following:
DistHashFunction. If a table uses some other hash function like modulo, then we consider the table-scan un-partitioned. We only allow those hash functions in table-scan which are also supported by KeySelector for hash exchange.PhysicalExchangetracks hash function separately to indicate the Hash Function to be used in KeySelector.Before, we would simply assume that a hash function we choose during planning could be used at runtime for shuffling, but our shuffle runtime was always using
absHashCode, which would have yielded incorrect results.Test Plan
UTs have decent coverage. I am also doing some manual testing and figuring out how to add tests for this