planner: generate physical plan for IndexMergePath (#11245)

cmd/explaintest/r/explain_indexmerge.result

@@ -0,0 +1,50 @@
+drop table if exists t;
+create table t (a int primary key, b int, c int, d int, e int, f int);
+create index tb on t (b);
+create index tc on t (c);
+create index td on t (d);
+load stats 's/explain_indexmerge_stats_t.json';
+set session tidb_enable_index_merge = on;
+explain select * from t where a < 50 or b < 50;
+id	count	task	operator info
+IndexMerge_11	98.00	root	
+├─TableScan_8	49.00	cop	table:t, range:[-inf,50), keep order:false
+├─IndexScan_9	49.00	cop	table:t, index:b, range:[-inf,50), keep order:false
+└─TableScan_10	98.00	cop	table:t, keep order:false
+explain select * from t where (a < 50 or b < 50) and f > 100;
+id	count	task	operator info
+IndexMerge_12	98.00	root	
+├─TableScan_8	49.00	cop	table:t, range:[-inf,50), keep order:false
+├─IndexScan_9	49.00	cop	table:t, index:b, range:[-inf,50), keep order:false
+└─Selection_11	98.00	cop	gt(test.t.f, 100)
+  └─TableScan_10	98.00	cop	table:t, keep order:false
+explain select * from t where a < 50 or b < 5000000;
+id	count	task	operator info
+TableReader_7	4000000.00	root	data:Selection_6
+└─Selection_6	4000000.00	cop	or(lt(test.t.a, 50), lt(test.t.b, 5000000))
+  └─TableScan_5	5000000.00	cop	table:t, range:[-inf,+inf], keep order:false
+explain select * from t where b < 50 or c < 50;
+id	count	task	operator info
+IndexMerge_11	98.00	root	
+├─IndexScan_8	49.00	cop	table:t, index:b, range:[-inf,50), keep order:false
+├─IndexScan_9	49.00	cop	table:t, index:c, range:[-inf,50), keep order:false
+└─TableScan_10	98.00	cop	table:t, keep order:false
+explain select * from t where b < 50 or c < 5000000;
+id	count	task	operator info
+TableReader_7	4000000.00	root	data:Selection_6
+└─Selection_6	4000000.00	cop	or(lt(test.t.b, 50), lt(test.t.c, 5000000))
+  └─TableScan_5	5000000.00	cop	table:t, range:[-inf,+inf], keep order:false
+explain select * from t where a < 50 or b < 50 or c < 50;
+id	count	task	operator info
+IndexMerge_12	147.00	root	
+├─TableScan_8	49.00	cop	table:t, range:[-inf,50), keep order:false
+├─IndexScan_9	49.00	cop	table:t, index:b, range:[-inf,50), keep order:false
+├─IndexScan_10	49.00	cop	table:t, index:c, range:[-inf,50), keep order:false
+└─TableScan_11	147.00	cop	table:t, keep order:false
+explain select * from t where (b < 10000 or c < 10000) and (a < 10 or d < 10) and f < 10;
+id	count	task	operator info
+IndexMerge_17	0.00	root	
+├─TableScan_13	9.00	cop	table:t, range:[-inf,10), keep order:false
+├─IndexScan_14	9.00	cop	table:t, index:d, range:[-inf,10), keep order:false
+└─Selection_16	0.00	cop	lt(test.t.f, 10), or(lt(test.t.b, 10000), lt(test.t.c, 10000))
+  └─TableScan_15	18.00	cop	table:t, keep order:false

cmd/explaintest/t/explain_indexmerge.test

@@ -0,0 +1,14 @@
+drop table if exists t;
+create table t (a int primary key, b int, c int, d int, e int, f int);
+create index tb on t (b);
+create index tc on t (c);
+create index td on t (d);
+load stats 's/explain_indexmerge_stats_t.json';
+set session tidb_enable_index_merge = on;
+explain select * from t where a < 50 or b < 50;
+explain select * from t where (a < 50 or b < 50) and f > 100;
+explain select * from t where a < 50 or b < 5000000;
+explain select * from t where b < 50 or c < 50;
+explain select * from t where b < 50 or c < 5000000;
+explain select * from t where a < 50 or b < 50 or c < 50;
+explain select * from t where (b < 10000 or c < 10000) and (a < 10 or d < 10) and f < 10;

planner/core/common_plans.go

@@ -622,6 +622,17 @@ func (e *Explain) explainPlanInRowFormat(p PhysicalPlan, taskType, indent string
 	case *PhysicalIndexLookUpReader:
 		e.explainPlanInRowFormat(copPlan.indexPlan, "cop", childIndent, false)
 		e.explainPlanInRowFormat(copPlan.tablePlan, "cop", childIndent, true)
+	case *PhysicalIndexMergeReader:
+		for i := 0; i < len(copPlan.partialPlans); i++ {
+			if copPlan.tablePlan == nil && i == len(copPlan.partialPlans)-1 {
+				e.explainPlanInRowFormat(copPlan.partialPlans[i], "cop", childIndent, true)
+			} else {
+				e.explainPlanInRowFormat(copPlan.partialPlans[i], "cop", childIndent, false)
+			}
+		}
+		if copPlan.tablePlan != nil {
+			e.explainPlanInRowFormat(copPlan.tablePlan, "cop", childIndent, true)
+		}
 	}
 }
 

planner/core/explain.go

@@ -144,6 +144,11 @@ func (p *PhysicalIndexLookUpReader) ExplainInfo() string {
 	return ""
 }
 
+// ExplainInfo implements PhysicalPlan interface.
+func (p *PhysicalIndexMergeReader) ExplainInfo() string {
+	return ""
+}
+
 // ExplainInfo implements PhysicalPlan interface.
 func (p *PhysicalUnionScan) ExplainInfo() string {
 	return string(expression.SortedExplainExpressionList(p.Conditions))