planner: fix the issue that binding cannot work when sql_select_limit…

… is enabled (#29789)
pingcap · Nov 23, 2021 · 18381f9 · 18381f9
1 parent 8b028b8
commit 18381f9
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Showing 3 changed files with 26 additions and 5 deletions.
diff --git a/executor/compiler.go b/executor/compiler.go
@@ -61,7 +61,6 @@ func (c *Compiler) Compile(ctx context.Context, stmtNode ast.StmtNode) (*ExecStm
 	if err != nil {
 		return nil, err
 	}
-	stmtNode = plannercore.TryAddExtraLimit(c.Ctx, stmtNode)
 
 	finalPlan, names, err := planner.Optimize(ctx, c.Ctx, stmtNode, ret.InfoSchema)
 	if err != nil {

diff --git a/planner/core/integration_test.go b/planner/core/integration_test.go
@@ -4719,6 +4719,26 @@ func (s *testIntegrationSuite) TestIssue27797(c *C) {
 	result.Check(testkit.Rows("<nil>"))
 }
 
+func (s *testIntegrationSuite) TestIssue27949(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t27949")
+	tk.MustExec("create table t27949 (a int, b int, key(b))")
+	tk.MustQuery("explain format = 'brief' select * from t27949 where b=1").Check(testkit.Rows("IndexLookUp 10.00 root  ",
+		"├─IndexRangeScan(Build) 10.00 cop[tikv] table:t27949, index:b(b) range:[1,1], keep order:false, stats:pseudo",
+		"└─TableRowIDScan(Probe) 10.00 cop[tikv] table:t27949 keep order:false, stats:pseudo"))
+	tk.MustExec("create global binding for select * from t27949 where b=1 using select * from t27949 ignore index(b) where b=1")
+	tk.MustQuery("explain format = 'brief' select * from t27949 where b=1").Check(testkit.Rows("TableReader 10.00 root  data:Selection",
+		"└─Selection 10.00 cop[tikv]  eq(test.t27949.b, 1)",
+		"  └─TableFullScan 10000.00 cop[tikv] table:t27949 keep order:false, stats:pseudo"))
+	tk.MustExec("set @@sql_select_limit=100")
+	tk.MustQuery("explain format = 'brief' select * from t27949 where b=1").Check(testkit.Rows("Limit 10.00 root  offset:0, count:100",
+		"└─TableReader 10.00 root  data:Limit",
+		"  └─Limit 10.00 cop[tikv]  offset:0, count:100",
+		"    └─Selection 10.00 cop[tikv]  eq(test.t27949.b, 1)",
+		"      └─TableFullScan 10000.00 cop[tikv] table:t27949 keep order:false, stats:pseudo"))
+}
+
 func (s *testIntegrationSuite) TestIssue28154(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")

diff --git a/planner/optimize.go b/planner/optimize.go
@@ -160,9 +160,10 @@ func Optimize(ctx context.Context, sctx sessionctx.Context, node ast.Node, is in
 			useBinding = false
 		}
 	}
-	if useBinding && sessVars.SelectLimit != math.MaxUint64 {
-		sessVars.StmtCtx.AppendWarning(errors.New("sql_select_limit is set, ignore SQL bindings"))
-		useBinding = false
+	if ok {
+		// add the extra Limit after matching the bind record
+		stmtNode = plannercore.TryAddExtraLimit(sctx, stmtNode)
+		node = stmtNode
 	}
 
 	var names types.NameSlice
@@ -234,7 +235,8 @@ func Optimize(ctx context.Context, sctx sessionctx.Context, node ast.Node, is in
 	defer func() {
 		sessVars.StmtCtx.StmtHints = savedStmtHints
 	}()
-	if sessVars.EvolvePlanBaselines && bestPlanFromBind != nil {
+	if sessVars.EvolvePlanBaselines && bestPlanFromBind != nil &&
+		sessVars.SelectLimit == math.MaxUint64 { // do not evolve this query if sql_select_limit is enabled
 		// Check bestPlanFromBind firstly to avoid nil stmtNode.
 		if _, ok := stmtNode.(*ast.SelectStmt); ok && !bindRecord.Bindings[0].Hint.ContainTableHint(plannercore.HintReadFromStorage) {
 			sessVars.StmtCtx.StmtHints = originStmtHints