cherry-pick: mannual cherry-pick 49421 back to release 7.1

executor/explain_test.go

@@ -702,3 +702,37 @@ func TestExplainFormatPlanCache(t *testing.T) {
 		tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
 	}
 }
+
+func TestIssues49377(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists employee")
+	tk.MustExec("create table employee (employee_id int, name varchar(20), dept_id int)")
+	tk.MustExec("insert into employee values (1, 'Furina', 1), (2, 'Klee', 1), (3, 'Eula', 1), (4, 'Diluc', 2), (5, 'Tartaglia', 2)")
+
+	tk.MustQuery("select 1,1,1 union all ( " +
+		"(select * from employee where dept_id = 1) " +
+		"union all  " +
+		"(select * from employee where dept_id = 1 order by employee_id) " +
+		"order by 1 limit 1 " +
+		");").Sort().Check(testkit.Rows("1 1 1", "1 Furina 1"))
+
+	tk.MustQuery("select 1,1,1 union all ( " +
+		"(select * from employee where dept_id = 1) " +
+		"union all  " +
+		"(select * from employee where dept_id = 1 order by employee_id) " +
+		"order by 1" +
+		");").Sort().Check(testkit.Rows("1 1 1", "1 Furina 1", "1 Furina 1", "2 Klee 1", "2 Klee 1", "3 Eula 1", "3 Eula 1"))
+
+	tk.MustQuery("select * from employee where dept_id = 1 " +
+		"union all " +
+		"(select * from employee where dept_id = 1 order by employee_id) " +
+		"union all" +
+		"(" +
+		"select * from employee where dept_id = 1 " +
+		"union all " +
+		"(select * from employee where dept_id = 1 order by employee_id) " +
+		"limit 1" +
+		");").Sort().Check(testkit.Rows("1 Furina 1", "1 Furina 1", "1 Furina 1", "2 Klee 1", "2 Klee 1", "3 Eula 1", "3 Eula 1"))
+}

parser/ast/dml.go

@@ -1550,6 +1550,8 @@ type SetOprSelectList struct {
 	With             *WithClause
 	AfterSetOperator *SetOprType
 	Selects          []Node
+	Limit            *Limit
+	OrderBy          *OrderByClause
 }
 
 // Restore implements Node interface.

parser/parser.go

@@ -19364,15 +19364,21 @@ yynewstate:
 			}
 			var setOprList2 []ast.Node
 			var with2 *ast.WithClause
+			var limit2 *ast.Limit
+			var orderBy2 *ast.OrderByClause
 			switch x := yyS[yypt-0].expr.(*ast.SubqueryExpr).Query.(type) {
 			case *ast.SelectStmt:
 				setOprList2 = []ast.Node{x}
 				with2 = x.With
 			case *ast.SetOprStmt:
+				// child setOprStmt's limit and order should also make sense
+				// we should separate it out from other normal SetOprSelectList.
 				setOprList2 = x.SelectList.Selects
 				with2 = x.With
+				limit2 = x.Limit
+				orderBy2 = x.OrderBy
 			}
-			nextSetOprList := &ast.SetOprSelectList{Selects: setOprList2, With: with2}
+			nextSetOprList := &ast.SetOprSelectList{Selects: setOprList2, With: with2, Limit: limit2, OrderBy: orderBy2}
 			nextSetOprList.AfterSetOperator = yyS[yypt-1].item.(*ast.SetOprType)
 			setOprList := append(setOprList1, nextSetOprList)
 			setOpr := &ast.SetOprStmt{SelectList: &ast.SetOprSelectList{Selects: setOprList}}

parser/parser.y

@@ -9994,15 +9994,21 @@ SetOprStmtWoutLimitOrderBy:
 		}
 		var setOprList2 []ast.Node
 		var with2 *ast.WithClause
+		var limit2 *ast.Limit
+		var orderBy2 *ast.OrderByClause
 		switch x := $3.(*ast.SubqueryExpr).Query.(type) {
 		case *ast.SelectStmt:
 			setOprList2 = []ast.Node{x}
 			with2 = x.With
 		case *ast.SetOprStmt:
+		    // child setOprStmt's limit and order should also make sense
+		    // we should separate it out from other normal SetOprSelectList.
 			setOprList2 = x.SelectList.Selects
 			with2 = x.With
+			limit2 = x.Limit
+			orderBy2 = x.OrderBy
 		}
-		nextSetOprList := &ast.SetOprSelectList{Selects: setOprList2, With: with2}
+		nextSetOprList := &ast.SetOprSelectList{Selects: setOprList2, With: with2, Limit: limit2, OrderBy: orderBy2}
 		nextSetOprList.AfterSetOperator = $2.(*ast.SetOprType)
 		setOprList := append(setOprList1, nextSetOprList)
 		setOpr := &ast.SetOprStmt{SelectList: &ast.SetOprSelectList{Selects: setOprList}}

planner/core/casetest/physical_plan_test.go

@@ -2433,6 +2433,32 @@ func TestCountStarForTiFlash(t *testing.T) {
 	}
 }
 
+func TestIssues49377Plan(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists employee")
+	tk.MustExec("create table employee (employee_id int, name varchar(20), dept_id int)")
+
+	var (
+		input  []string
+		output []struct {
+			SQL     string
+			Plan    []string
+			Warning []string
+		}
+	)
+	planSuiteData := GetPlanSuiteData()
+	planSuiteData.LoadTestCases(t, &input, &output)
+	for i, ts := range input {
+		testdata.OnRecord(func() {
+			output[i].SQL = ts
+			output[i].Plan = testdata.ConvertRowsToStrings(tk.MustQuery("explain format = 'brief' " + ts).Rows())
+		})
+		tk.MustQuery("explain format = 'brief' " + ts).Check(testkit.Rows(output[i].Plan...))
+	}
+}
+
 func TestHashAggPushdownToTiFlashCompute(t *testing.T) {
 	var (
 		input  []string

planner/core/casetest/testdata/plan_suite_in.json

@@ -1332,5 +1332,14 @@
       "select * from tcommon where (a = 1 and c = 2) or (b = 1) order by c limit 2",
       "select * from thash use index(idx_ac, idx_bc) where a = 1 or b = 1 order by c limit 2"
     ]
+  },
+  {
+    "name": "TestIssues49377Plan",
+    "cases": [
+      "select 1,1,1 union all ((select * from employee where dept_id = 1)  union all ( select * from employee where dept_id = 1 order by employee_id ) order by 1 );",
+      "select 1,1,1 union all ((select * from employee where dept_id = 1)  union all ( select * from employee where dept_id = 1 order by employee_id ) order by 1 limit 1);",
+      "select * from employee where dept_id = 1 union all ( select * from employee where dept_id = 1 order by employee_id) union all ( select * from employee where dept_id = 1 union all ( select * from employee where dept_id = 1 order by employee_id ) limit 1);",
+      "select * from employee where dept_id = 1 union all ( select * from employee where dept_id = 1 order by employee_id) union all ( select * from employee where dept_id = 1 union all ( select * from employee where dept_id = 1 order by employee_id ) order by 1 limit 1);"
+    ]
   }
 ]

planner/core/casetest/testdata/plan_suite_out.json

@@ -8721,5 +8721,103 @@
         ]
       }
     ]
+  },
+  {
+    "Name": "TestIssues49377Plan",
+    "Cases": [
+      {
+        "SQL": "select 1,1,1 union all ((select * from employee where dept_id = 1)  union all ( select * from employee where dept_id = 1 order by employee_id ) order by 1 );",
+        "Plan": [
+          "Union 21.00 root  ",
+          "├─Projection 1.00 root  1->Column#15, 1->Column#16, 1->Column#17",
+          "│ └─TableDual 1.00 root  rows:1",
+          "└─Projection 20.00 root  cast(Column#12, bigint(11) BINARY)->Column#15, Column#13, cast(Column#14, bigint(11) BINARY)->Column#17",
+          "  └─Sort 20.00 root  Column#12",
+          "    └─Union 20.00 root  ",
+          "      ├─TableReader 10.00 root  data:Selection",
+          "      │ └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "      │   └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo",
+          "      └─Sort 10.00 root  test.employee.employee_id",
+          "        └─TableReader 10.00 root  data:Selection",
+          "          └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "            └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo"
+        ],
+        "Warning": null
+      },
+      {
+        "SQL": "select 1,1,1 union all ((select * from employee where dept_id = 1)  union all ( select * from employee where dept_id = 1 order by employee_id ) order by 1 limit 1);",
+        "Plan": [
+          "Union 2.00 root  ",
+          "├─Projection 1.00 root  1->Column#15, 1->Column#16, 1->Column#17",
+          "│ └─TableDual 1.00 root  rows:1",
+          "└─Projection 1.00 root  cast(Column#12, bigint(11) BINARY)->Column#15, Column#13, cast(Column#14, bigint(11) BINARY)->Column#17",
+          "  └─TopN 1.00 root  Column#12, offset:0, count:1",
+          "    └─Union 2.00 root  ",
+          "      ├─TopN 1.00 root  test.employee.employee_id, offset:0, count:1",
+          "      │ └─TableReader 1.00 root  data:TopN",
+          "      │   └─TopN 1.00 cop[tikv]  test.employee.employee_id, offset:0, count:1",
+          "      │     └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "      │       └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo",
+          "      └─TopN 1.00 root  test.employee.employee_id, offset:0, count:1",
+          "        └─TableReader 1.00 root  data:TopN",
+          "          └─TopN 1.00 cop[tikv]  test.employee.employee_id, offset:0, count:1",
+          "            └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "              └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo"
+        ],
+        "Warning": null
+      },
+      {
+        "SQL": "select * from employee where dept_id = 1 union all ( select * from employee where dept_id = 1 order by employee_id) union all ( select * from employee where dept_id = 1 union all ( select * from employee where dept_id = 1 order by employee_id ) limit 1);",
+        "Plan": [
+          "Union 21.00 root  ",
+          "├─TableReader 10.00 root  data:Selection",
+          "│ └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "│   └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo",
+          "├─Sort 10.00 root  test.employee.employee_id",
+          "│ └─TableReader 10.00 root  data:Selection",
+          "│   └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "│     └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo",
+          "└─Limit 1.00 root  offset:0, count:1",
+          "  └─Union 1.00 root  ",
+          "    ├─Limit 1.00 root  offset:0, count:1",
+          "    │ └─TableReader 1.00 root  data:Limit",
+          "    │   └─Limit 1.00 cop[tikv]  offset:0, count:1",
+          "    │     └─Selection 1.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "    │       └─TableFullScan 1000.00 cop[tikv] table:employee keep order:false, stats:pseudo",
+          "    └─TopN 1.00 root  test.employee.employee_id, offset:0, count:1",
+          "      └─TableReader 1.00 root  data:TopN",
+          "        └─TopN 1.00 cop[tikv]  test.employee.employee_id, offset:0, count:1",
+          "          └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "            └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo"
+        ],
+        "Warning": null
+      },
+      {
+        "SQL": "select * from employee where dept_id = 1 union all ( select * from employee where dept_id = 1 order by employee_id) union all ( select * from employee where dept_id = 1 union all ( select * from employee where dept_id = 1 order by employee_id ) order by 1 limit 1);",
+        "Plan": [
+          "Union 21.00 root  ",
+          "├─TableReader 10.00 root  data:Selection",
+          "│ └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "│   └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo",
+          "├─Sort 10.00 root  test.employee.employee_id",
+          "│ └─TableReader 10.00 root  data:Selection",
+          "│   └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "│     └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo",
+          "└─TopN 1.00 root  Column#17, offset:0, count:1",
+          "  └─Union 2.00 root  ",
+          "    ├─TopN 1.00 root  test.employee.employee_id, offset:0, count:1",
+          "    │ └─TableReader 1.00 root  data:TopN",
+          "    │   └─TopN 1.00 cop[tikv]  test.employee.employee_id, offset:0, count:1",
+          "    │     └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "    │       └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo",
+          "    └─TopN 1.00 root  test.employee.employee_id, offset:0, count:1",
+          "      └─TableReader 1.00 root  data:TopN",
+          "        └─TopN 1.00 cop[tikv]  test.employee.employee_id, offset:0, count:1",
+          "          └─Selection 10.00 cop[tikv]  eq(test.employee.dept_id, 1)",
+          "            └─TableFullScan 10000.00 cop[tikv] table:employee keep order:false, stats:pseudo"
+        ],
+        "Warning": null
+      }
+    ]
   }
 ]

planner/core/logical_plan_builder.go

@@ -1824,6 +1824,12 @@ func (b *PlanBuilder) buildSetOpr(ctx context.Context, setOpr *ast.SetOprStmt) (
 				if *x.AfterSetOperator != ast.Intersect && *x.AfterSetOperator != ast.IntersectAll {
 					breakIteration = true
 				}
+				if x.Limit != nil || x.OrderBy != nil {
+					// when SetOprSelectList's limit and order-by is not nil, it means itself is converted from
+					// an independent ast.SetOprStmt in parser, its data should be evaluated first, and ordered
+					// by given items and conduct a limit on it, then it can only be integrated with other brothers.
+					breakIteration = true
+				}
 			}
 			if breakIteration {
 				break
@@ -1922,7 +1928,7 @@ func (b *PlanBuilder) buildIntersect(ctx context.Context, selects []ast.Node) (L
 		leftPlan, err = b.buildSelect(ctx, x)
 	case *ast.SetOprSelectList:
 		afterSetOperator = x.AfterSetOperator
-		leftPlan, err = b.buildSetOpr(ctx, &ast.SetOprStmt{SelectList: x, With: x.With})
+		leftPlan, err = b.buildSetOpr(ctx, &ast.SetOprStmt{SelectList: x, With: x.With, Limit: x.Limit, OrderBy: x.OrderBy})
 	}
 	if err != nil {
 		return nil, nil, err
@@ -1946,7 +1952,7 @@ func (b *PlanBuilder) buildIntersect(ctx context.Context, selects []ast.Node) (L
 				// TODO: support intersect all
 				return nil, nil, errors.Errorf("TiDB do not support intersect all")
 			}
-			rightPlan, err = b.buildSetOpr(ctx, &ast.SetOprStmt{SelectList: x, With: x.With})
+			rightPlan, err = b.buildSetOpr(ctx, &ast.SetOprStmt{SelectList: x, With: x.With, Limit: x.Limit, OrderBy: x.OrderBy})
 		}
 		if err != nil {
 			return nil, nil, err