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plan: build anti semi join for NOT EXISTS #7842

Merged
merged 9 commits into from
Oct 9, 2018
Merged

plan: build anti semi join for NOT EXISTS #7842

merged 9 commits into from
Oct 9, 2018

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eurekaka
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@eurekaka eurekaka commented Oct 9, 2018 •
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What problem does this PR solve?

Fix #7837

What is changed and how it works?

remove Not UnaryOperationExpr from AST, and store NOT in ExistsSubqueryExpr.

After this PR:

mysql> explain select * from t1 where not exists (select * from t2 where t1.a = t2.a);
+------------------------+----------+------+------------------------------------------------------------------------+
| id                     | count    | task | operator info                                                          |
+------------------------+----------+------+------------------------------------------------------------------------+
| HashLeftJoin_9         | 8000.00  | root | anti semi join, inner:TableReader_13, equal:[eq(test.t1.a, test.t2.a)] |
| ├─TableReader_11       | 10000.00 | root | data:TableScan_10                                                      |
| │ └─TableScan_10       | 10000.00 | cop  | table:t1, range:[-inf,+inf], keep order:false, stats:pseudo            |
| └─TableReader_13       | 10000.00 | root | data:TableScan_12                                                      |
|   └─TableScan_12       | 10000.00 | cop  | table:t2, range:[-inf,+inf], keep order:false, stats:pseudo            |
+------------------------+----------+------+------------------------------------------------------------------------+
5 rows in set (0.00 sec)

Check List

Tests

  • Unit test
  • Integration test

Side effects

N/A

Related changes

N/A

@eurekaka eurekaka added type/enhancement The issue or PR belongs to an enhancement. status/WIP sig/planner SIG: Planner labels Oct 9, 2018
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eurekaka commented Oct 9, 2018

/run-all-tests

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eurekaka commented Oct 9, 2018

/run-all-tests

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eurekaka commented Oct 9, 2018

@zz-jason @winoros @XuHuaiyu PTAL

zz-jason
zz-jason reviewed Oct 9, 2018
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LGTM

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zz-jason commented Oct 9, 2018

/run-all-tests

@zz-jason zz-jason added the status/LGT1 Indicates that a PR has LGTM 1. label Oct 9, 2018
XuHuaiyu
XuHuaiyu reviewed Oct 9, 2018
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planner/core/expression_rewriter.go
@@ -562,7 +562,7 @@ func (er *expressionRewriter) handleExistSubquery(v *ast.ExistsSubqueryExpr) (as
er.err = errors.Trace(err)
return v, true
}
if len(rows) > 0 {
if (len(rows) > 0 && !v.Not) || (len(rows) == 0 && v.Not) {
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what does this check mean?

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rows is the result of the subquery evaluated by EvalSubquery(), it directly set the result of exists subquery according to rows.

@XuHuaiyu XuHuaiyu changed the title [WIP] plan: build anti semi join for NOT EXISTS plan: build anti semi join for NOT EXISTS Oct 9, 2018
winoros
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lgtm

@XuHuaiyu XuHuaiyu added status/LGT2 Indicates that a PR has LGTM 2. and removed status/LGT1 Indicates that a PR has LGTM 1. labels Oct 9, 2018
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eurekaka commented Oct 9, 2018

/run-mybatis-test
/run-sqllogic-test

@eurekaka eurekaka merged commit d60a1a2 into pingcap:master Oct 9, 2018
@eurekaka eurekaka deleted the not_exists_anti branch October 9, 2018 08:57
@XuHuaiyu XuHuaiyu mentioned this pull request Nov 15, 2018
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@tiancaiamao tiancaiamao mentioned this pull request Nov 22, 2018
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@eurekaka eurekaka mentioned this pull request Dec 18, 2018
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eurekaka added a commit to eurekaka/parser that referenced this pull request Jul 17, 2019
@eurekaka
*: add Not flag for ExistsSubqueryExpr
c663361 
Parser part of the cherry-pick for pingcap/tidb#7842
@eurekaka eurekaka mentioned this pull request Jul 17, 2019
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eurekaka added a commit to eurekaka/tidb that referenced this pull request Jul 17, 2019
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planner: build anti semi join for NOT EXISTS (pingcap#7842)
a16772e
@eurekaka eurekaka mentioned this pull request Jul 17, 2019
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eurekaka added a commit that referenced this pull request Jul 18, 2019
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planner: build anti semi join for NOT EXISTS (#7842) (#11291)
6626b49
alivxxx pushed a commit to alivxxx/tidb that referenced this pull request Jul 24, 2019
@eurekaka @alivxxx
planner: build anti semi join for NOT EXISTS (pingcap#7842) (pingca…
7dbabf1 
…p#11291)
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Can this really make performance? Is there some test cases or benckmark ?

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@XuHuaiyu XuHuaiyu XuHuaiyu approved these changes

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build anti semi join for NOT EXISTS instead of left outer semi join with NOT selection
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