[opt](nereids)prune unused column after push down common column from agg #46627
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run buildall |
TPC-H: Total hot run time: 30745 ms |
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run buildall |
TPC-H: Total hot run time: 28707 ms |
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run buildall |
TPC-H: Total hot run time: 26186 ms |
TPC-DS: Total hot run time: 182387 ms |
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run buildall |
morrySnow
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Jan 9, 2025
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| Expr result = ExpressionTranslator.translate(e, context); | ||
| if (result == null) { | ||
| throw new RuntimeException("translate " + e + " failed"); | ||
| } | ||
| return result; |
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could we get more info about translate failed and print them in log?
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| .flatMap(expr -> expr.getInputSlots().stream()) | ||
| .collect(Collectors.toSet()); | ||
| for (NamedExpression expr : project.getProjects()) { | ||
| if (!(expr instanceof SlotReference) || newInputSlots.contains(expr)) { |
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why need !(expr instanceof SlotReference)?
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if it is not slot, it is alias. if it is alias, it must be used by Aggregate in 2 cases:
- directly used by Agg after rewrite
- used by inferred common expression.
In both cases, alias should not be pruned.
TPC-H: Total hot run time: 31992 ms |
TPC-DS: Total hot run time: 193426 ms |
ClickBench: Total hot run time: 30.76 s |
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run buildall |
TPC-H: Total hot run time: 32550 ms |
TPC-DS: Total hot run time: 195265 ms |
ClickBench: Total hot run time: 31 s |
starocean999
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Jan 15, 2025
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PR approved by at least one committer and no changes requested. |
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LiBinfeng-01
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Jan 15, 2025
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…agg (#46627) ### What problem does this PR solve? after extracting common expressions for agg, the underlying projection may project redundant columns. for example: original plan Agg(groupkey=[A+B, A+B+1]) --> project(A, B) after extracting, "A+B as C" is detected as a common expression, and the plan becomes Agg(groupKey=[C, C+1]) -->project(A, B, A+B as C) here A, B should not be projected, since they are not used any more. so the optimal plan is Agg(groupKey=[C, C+1]) -->project(A+B as C) Related PR: #40473
lzyy2024
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Feb 21, 2025
…agg (apache#46627) ### What problem does this PR solve? after extracting common expressions for agg, the underlying projection may project redundant columns. for example: original plan Agg(groupkey=[A+B, A+B+1]) --> project(A, B) after extracting, "A+B as C" is detected as a common expression, and the plan becomes Agg(groupKey=[C, C+1]) -->project(A, B, A+B as C) here A, B should not be projected, since they are not used any more. so the optimal plan is Agg(groupKey=[C, C+1]) -->project(A+B as C) Related PR: apache#40473
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What problem does this PR solve?
after extracting common expressions for agg, the underlying projection may project redundant columns.
for example:
original plan
Agg(groupkey=[A+B, A+B+1])
--> project(A, B)
after extracting, "A+B as C" is detected as a common expression, and the plan becomes
Agg(groupKey=[C, C+1])
-->project(A, B, A+B as C)
here A, B should not be projected, since they are not used any more. so the optimal plan is
Agg(groupKey=[C, C+1])
-->project(A+B as C)
Related PR: #40473
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