Planner: Avoid injecting redundant projection below LogicalJoin (ping…

…cap#11662)
ti-srebot · Aug 19, 2019 · 69c0c3b · 69c0c3b
1 parent fb166e8
commit 69c0c3b
Show file tree

Hide file tree

Showing 4 changed files with 66 additions and 22 deletions.
diff --git a/cmd/explaintest/r/explain_easy.result b/cmd/explaintest/r/explain_easy.result
@@ -11,15 +11,15 @@ set @@session.tidb_hashagg_partial_concurrency = 1;
 set @@session.tidb_hashagg_final_concurrency = 1;
 explain select * from t3 where exists (select s.a from t3 s having sum(s.a) = t3.a );
 id	count	task	operator info
-Projection_12	8000.00	root	test.t3.a, test.t3.b, test.t3.c, test.t3.d
-└─HashLeftJoin_13	8000.00	root	semi join, inner:StreamAgg_29, equal:[eq(cast(test.t3.a), sel_agg_1)]
-  ├─Projection_14	10000.00	root	test.t3.a, test.t3.b, test.t3.c, test.t3.d, cast(test.t3.a)
-  │ └─TableReader_16	10000.00	root	data:TableScan_15
-  │   └─TableScan_15	10000.00	cop	table:t3, range:[-inf,+inf], keep order:false, stats:pseudo
-  └─StreamAgg_29	1.00	root	funcs:sum(col_0)
-    └─TableReader_30	1.00	root	data:StreamAgg_21
-      └─StreamAgg_21	1.00	cop	funcs:sum(test.s.a)
-        └─TableScan_28	10000.00	cop	table:s, range:[-inf,+inf], keep order:false, stats:pseudo
+Projection_11	8000.00	root	test.t3.a, test.t3.b, test.t3.c, test.t3.d
+└─HashLeftJoin_12	8000.00	root	semi join, inner:StreamAgg_27, equal:[eq(cast(test.t3.a), sel_agg_1)]
+  ├─Projection_13	10000.00	root	test.t3.a, test.t3.b, test.t3.c, test.t3.d, cast(test.t3.a)
+  │ └─TableReader_15	10000.00	root	data:TableScan_14
+  │   └─TableScan_14	10000.00	cop	table:t3, range:[-inf,+inf], keep order:false, stats:pseudo
+  └─StreamAgg_27	1.00	root	funcs:sum(col_0)
+    └─TableReader_28	1.00	root	data:StreamAgg_19
+      └─StreamAgg_19	1.00	cop	funcs:sum(test.s.a)
+        └─TableScan_26	10000.00	cop	table:s, range:[-inf,+inf], keep order:false, stats:pseudo
 explain select * from t1;
 id	count	task	operator info
 TableReader_5	10000.00	root	data:TableScan_4

diff --git a/cmd/explaintest/r/explain_easy_stats.result b/cmd/explaintest/r/explain_easy_stats.result
@@ -14,15 +14,15 @@ set @@session.tidb_hashagg_partial_concurrency = 1;
 set @@session.tidb_hashagg_final_concurrency = 1;
 explain select * from t3 where exists (select s.a from t3 s having sum(s.a) = t3.a );
 id	count	task	operator info
-Projection_12	1600.00	root	test.t3.a, test.t3.b, test.t3.c, test.t3.d
-└─HashLeftJoin_13	1600.00	root	semi join, inner:StreamAgg_29, equal:[eq(cast(test.t3.a), sel_agg_1)]
-  ├─Projection_14	2000.00	root	test.t3.a, test.t3.b, test.t3.c, test.t3.d, cast(test.t3.a)
-  │ └─TableReader_16	2000.00	root	data:TableScan_15
-  │   └─TableScan_15	2000.00	cop	table:t3, range:[-inf,+inf], keep order:false
-  └─StreamAgg_29	1.00	root	funcs:sum(col_0)
-    └─TableReader_30	1.00	root	data:StreamAgg_21
-      └─StreamAgg_21	1.00	cop	funcs:sum(test.s.a)
-        └─TableScan_28	2000.00	cop	table:s, range:[-inf,+inf], keep order:false
+Projection_11	1600.00	root	test.t3.a, test.t3.b, test.t3.c, test.t3.d
+└─HashLeftJoin_12	1600.00	root	semi join, inner:StreamAgg_27, equal:[eq(cast(test.t3.a), sel_agg_1)]
+  ├─Projection_13	2000.00	root	test.t3.a, test.t3.b, test.t3.c, test.t3.d, cast(test.t3.a)
+  │ └─TableReader_15	2000.00	root	data:TableScan_14
+  │   └─TableScan_14	2000.00	cop	table:t3, range:[-inf,+inf], keep order:false
+  └─StreamAgg_27	1.00	root	funcs:sum(col_0)
+    └─TableReader_28	1.00	root	data:StreamAgg_19
+      └─StreamAgg_19	1.00	cop	funcs:sum(test.s.a)
+        └─TableScan_26	2000.00	cop	table:s, range:[-inf,+inf], keep order:false
 explain select * from t1;
 id	count	task	operator info
 TableReader_5	1999.00	root	data:TableScan_4

diff --git a/planner/core/logical_plan_test.go b/planner/core/logical_plan_test.go
@@ -2642,3 +2642,29 @@ func (s *testPlanSuite) TestFastPlanContextTables(c *C) {
 		}
 	}
 }
+
+func (s *testPlanSuite) TestUpdateEQCond(c *C) {
+	defer testleak.AfterTest(c)()
+	tests := []struct {
+		sql  string
+		best string
+	}{
+		{
+			sql:  "select t1.a from t t1, t t2 where t1.a = t2.a+1",
+			best: "Join{DataScan(t1)->DataScan(t2)->Projection}(test.t1.a,plus(test.t2.a, 1))->Projection",
+		},
+	}
+	ctx := context.TODO()
+	for i, tt := range tests {
+		comment := Commentf("case:%v sql:%s", i, tt.sql)
+		stmt, err := s.ParseOneStmt(tt.sql, "", "")
+		c.Assert(err, IsNil, comment)
+		Preprocess(s.ctx, stmt, s.is)
+		builder := NewPlanBuilder(MockContext(), s.is)
+		p, err := builder.Build(ctx, stmt)
+		c.Assert(err, IsNil)
+		p, err = logicalOptimize(ctx, builder.optFlag, p.(LogicalPlan))
+		c.Assert(err, IsNil)
+		c.Assert(ToString(p), Equals, tt.best, comment)
+	}
+}
diff --git a/planner/core/rule_predicate_push_down.go b/planner/core/rule_predicate_push_down.go
@@ -219,11 +219,29 @@ func (p *LogicalJoin) updateEQCond() {
 		}
 	}
 	if len(lKeys) > 0 {
-		lProj := p.getProj(0)
-		rProj := p.getProj(1)
+		needLProj, needRProj := false, false
 		for i := range lKeys {
-			lKey := lProj.appendExpr(lKeys[i])
-			rKey := rProj.appendExpr(rKeys[i])
+			_, lOk := lKeys[i].(*expression.Column)
+			_, rOk := rKeys[i].(*expression.Column)
+			needLProj = needLProj || !lOk
+			needRProj = needRProj || !rOk
+		}
+
+		var lProj, rProj *LogicalProjection
+		if needLProj {
+			lProj = p.getProj(0)
+		}
+		if needRProj {
+			rProj = p.getProj(1)
+		}
+		for i := range lKeys {
+			lKey, rKey := lKeys[i], rKeys[i]
+			if lProj != nil {
+				lKey = lProj.appendExpr(lKey)
+			}
+			if rProj != nil {
+				rKey = rProj.appendExpr(rKey)
+			}
 			eqCond := expression.NewFunctionInternal(p.ctx, ast.EQ, types.NewFieldType(mysql.TypeTiny), lKey, rKey)
 			p.EqualConditions = append(p.EqualConditions, eqCond.(*expression.ScalarFunction))
 		}