Include ALL modifier for set operators in multi-stage query engine physical explain plan #13166
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…ysical explain plan
yashmayya
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| @Override | ||
| public String explain() { | ||
| return _setOpType.toString(); | ||
| return _all ? _setOpType.toString() + "_ALL" : _setOpType.toString(); |
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Does it works in Union? AFAIR union always behaves as all = true. Is this attribute always true in union?
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Yeah it does look like this attribute is always true for the union set operation (i.e., regardless of whether we use UNION or UNION ALL). I guess that isn't inaccurate though since the actual semantics being implemented are indeed the UNION ALL semantics and the logical plan also contains LogicalUnion(all=[true]) for both UNION and UNION ALL?
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Ah, I just noticed that the query plan for UNION contains an aggregation on top to only get unique values from the result of the UNION ALL, interesting.
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## master #13166 +/- ##
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+ Coverage 61.75% 62.15% +0.40%
+ Complexity 207 198 -9
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Files 2436 2517 +81
Lines 133233 137895 +4662
Branches 20636 21340 +704
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+ Hits 82274 85713 +3439
- Misses 44911 45798 +887
- Partials 6048 6384 +336
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…ysical explain plan (apache#13166)
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INTERSECT ALLandEXCEPT ALLset operators in the multi-stage query engine.ALLmodifier was used.EXPLAIN PLAN FOR SELECT * FROM (SELECT a FROM A) EXCEPT ALL (SELECT b FROM B);looks like this (Calcite syntax):ALLmodifier was used. So the output for bothEXPLAIN IMPLEMENTATION PLAN FOR SELECT * FROM (SELECT a FROM A) EXCEPT ALL (SELECT b FROM B);andEXPLAIN IMPLEMENTATION PLAN FOR SELECT * FROM (SELECT a FROM A) EXCEPT (SELECT b FROM B);would look the same:SetOpNode::explainwhich is called in thePhysicalExplainPlanVisitorhere. The output forEXPLAIN IMPLEMENTATION PLAN FOR SELECT * FROM (SELECT a FROM A) EXCEPT ALL (SELECT b FROM B);now looks like: