*: implement index nested loop join #2945
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hanfei1991
reviewed
Mar 30, 2017
plan/physical_plan_builder.go
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| @@ -571,6 +571,205 @@ func (p *Join) convert2PhysicalPlanRight(prop *requiredProperty, innerJoin bool) | |||
| return resultInfo, nil | |||
| } | |||
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| // buildSelectionWithConds will build a selection use the conditions of join and convert one side's column to correlated column. | |||
| // This is called when build nested loop join. | |||
| func (p *Join) buildSelectionWithConds(left bool) (*Selection, []*expression.CorrelatedColumn) { | |||
hanfei1991
reviewed
Mar 30, 2017
plan/physical_plan_builder.go
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| selection.SetSchema(innerChild.Schema().Clone()) | ||
| selection.SetChildren(innerChild) | ||
| if left { | ||
| conds = make([]expression.Expression, 0, len(p.EqualConditions)+len(p.RightConditions)+len(p.OtherConditions)) |
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Do you need to resolve again for other condition? add test for it
hanfei1991
reviewed
Mar 30, 2017
plan/physical_plan_builder.go
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| ap := &PhysicalApply{ | ||
| PhysicalJoin: resultInfo.p, | ||
| OuterSchema: corCols, | ||
| } |
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But self is one part of baseLogicalPlan not one part of basePlan.
hanfei1991
reviewed
Mar 30, 2017
plan/physical_plan_builder.go
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| join.tp = "NestedLoopJoinLeft" | ||
| join.allocator = p.allocator | ||
| join.initIDAndContext(p.ctx) | ||
| join.SetChildren(lInfo.p, rInfo.p) |
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Can we offer a way to choose the outer table of index join ? |
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Now we can use hint to choose the outer table. |
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LGTM |
shenli
reviewed
Mar 31, 2017
executor/join_test.go
Outdated
| tk.MustQuery("select /*+ TIDB_INLJ(t, t1) */ * from t right outer join t1 on t.a=t1.a").Check(testkit.Rows("1 1 1 2", "1 1 1 3", "3 3 3 4", "<nil> <nil> 4 5")) | ||
| tk.MustQuery("select /*+ TIDB_INLJ(t, t1) */ avg(t.b) from t right outer join t1 on t.a=t1.a").Check(testkit.Rows("1.6667")) | ||
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| _, err = tk.Exec("select /*+ TIDB_INLJ(t) TIDB_SMJ(t) * from t join t1 on t.a=t1.a") |
coocood
reviewed
Mar 31, 2017
plan/physical_plan_builder.go
Outdated
| @@ -1004,7 +1246,7 @@ func (p *Union) convert2PhysicalPlan(prop *requiredProperty) (*physicalPlanInfo, | |||
| // makeScanController will try to build a selection that controls the below scan's filter condition, | |||
| // and return a physicalPlanInfo. If the onlyJudge is true, it will only check whether this selection | |||
| // can become a scan controller without building the physical plan. | |||
| func (p *Selection) makeScanController(onlyJudge bool) (*physicalPlanInfo, bool) { | |||
| func (p *Selection) makeScanController(onlyJudge bool) (*physicalPlanInfo, int) { | |||
coocood
reviewed
Mar 31, 2017
plan/physical_plan_builder.go
Outdated
| } | ||
| ts := &PhysicalTableScan{ | ||
| cond, _ := expression.SubstituteCorCol2Constant(expr) |
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Isn't the condition already been substituted at the beginning of the function?
coocood
reviewed
Mar 31, 2017
plan/physical_plan_builder.go
Outdated
| } | ||
| ts := &PhysicalTableScan{ | ||
| // else will judge whether can build a index scan or just build a index scan. |
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Search the keyword judge replace them all, include comments.
hanfei1991
reviewed
Mar 31, 2017
| colMapper: make(map[*ast.ColumnNameExpr]int), | ||
| is: is, | ||
| } | ||
| p := builder.build(stmt) |
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combine the line 1129 to 1142 as doOptimize to avoid the Cache plan.
coocood
reviewed
Apr 1, 2017
plan/physical_plan_builder.go
Outdated
| better = better || (chosenPlan.accessEqualCount == is.accessEqualCount && chosenPlan.accessInAndEqCount < is.accessInAndEqCount) | ||
| _, _, accessEqualCount, accessInAndEqCount := DetachIndexScanConditions(condsBackUp, idx) | ||
| better := chosenPlan == nil || bestEqualCount < accessEqualCount | ||
| better = better || (bestEqualCount == accessEqualCount && bestInAndEqCount < accessInAndEqCount) |
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I think simply check access equal count is enough.
better := accessEqualCount >= bestEqualCount
Other wise, we need to add tests for accesInAndEqCount.
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When one of join's children is a scan and there are equal conditions that use the index of this scan. We can build this join to a nested loop join and build this scan using index to look up.
Currently index nested loop join is controlled by the hint
/*+ TIDB_INLJ(t1, t2) */not cost-based.And only the table in
TIDB_INLJ()will be considered as outer table of the join.