From 14066b262e80222eb558d680f29b68b357f21204 Mon Sep 17 00:00:00 2001
From: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
Date: Wed, 10 Aug 2022 11:32:49 +0800
Subject: [PATCH] executor: prevent sending cop request for show columns
 (#36613) (#36820)

close pingcap/tidb#36426, ref pingcap/tidb#36496
---
 executor/prepared.go                          |  2 +-
 executor/show.go                              |  3 +-
 planner/core/expression_rewriter.go           |  6 +--
 planner/core/indexmerge_test.go               |  2 +-
 planner/core/logical_plan_test.go             | 20 ++++----
 .../core/memtable_predicate_extractor_test.go |  2 +-
 planner/core/optimizer.go                     |  2 +-
 planner/core/planbuilder.go                   | 48 ++++++++++++++-----
 planner/core/planbuilder_test.go              |  4 +-
 planner/core/prepare_test.go                  |  2 +-
 planner/core/stats_test.go                    |  2 +-
 planner/optimize.go                           |  4 +-
 12 files changed, 62 insertions(+), 35 deletions(-)

diff --git a/executor/prepared.go b/executor/prepared.go
index 832252a82ec93..dd623d73711f0 100644
--- a/executor/prepared.go
+++ b/executor/prepared.go
@@ -199,7 +199,7 @@ func (e *PrepareExec) Next(ctx context.Context, req *chunk.Chunk) error {
 	var p plannercore.Plan
 	e.ctx.GetSessionVars().PlanID = 0
 	e.ctx.GetSessionVars().PlanColumnID = 0
-	destBuilder, _ := plannercore.NewPlanBuilder(e.ctx, e.is, &hint.BlockHintProcessor{})
+	destBuilder, _ := plannercore.NewPlanBuilder().Init(e.ctx, e.is, &hint.BlockHintProcessor{})
 	p, err = destBuilder.Build(ctx, stmt)
 	if err != nil {
 		return err
diff --git a/executor/show.go b/executor/show.go
index 7c73eabf57f10..6d8638a717680 100644
--- a/executor/show.go
+++ b/executor/show.go
@@ -1693,7 +1693,8 @@ func (e *ShowExec) fetchShowBuiltins() error {
 func tryFillViewColumnType(ctx context.Context, sctx sessionctx.Context, is infoschema.InfoSchema, dbName model.CIStr, tbl *model.TableInfo) error {
 	if tbl.IsView() {
 		// Retrieve view columns info.
-		planBuilder, _ := plannercore.NewPlanBuilder(sctx, is, &hint.BlockHintProcessor{})
+		planBuilder, _ := plannercore.NewPlanBuilder(
+			plannercore.PlanBuilderOptNoExecution{}).Init(sctx, is, &hint.BlockHintProcessor{})
 		if viewLogicalPlan, err := planBuilder.BuildDataSourceFromView(ctx, dbName, tbl); err == nil {
 			viewSchema := viewLogicalPlan.Schema()
 			viewOutputNames := viewLogicalPlan.OutputNames()
diff --git a/planner/core/expression_rewriter.go b/planner/core/expression_rewriter.go
index 6eaf5e21f7f8c..666484f8bef0b 100644
--- a/planner/core/expression_rewriter.go
+++ b/planner/core/expression_rewriter.go
@@ -66,7 +66,7 @@ func rewriteAstExpr(sctx sessionctx.Context, expr ast.ExprNode, schema *expressi
 	if sctx.GetSessionVars().TxnCtx.InfoSchema != nil {
 		is = sctx.GetSessionVars().TxnCtx.InfoSchema.(infoschema.InfoSchema)
 	}
-	b, savedBlockNames := NewPlanBuilder(sctx, is, &hint.BlockHintProcessor{})
+	b, savedBlockNames := NewPlanBuilder().Init(sctx, is, &hint.BlockHintProcessor{})
 	fakePlan := LogicalTableDual{}.Init(sctx, 0)
 	if schema != nil {
 		fakePlan.schema = schema
@@ -780,7 +780,7 @@ func (er *expressionRewriter) handleExistSubquery(ctx context.Context, v *ast.Ex
 		return v, true
 	}
 	np = er.popExistsSubPlan(np)
-	if len(ExtractCorrelatedCols4LogicalPlan(np)) > 0 {
+	if er.b.disableSubQueryPreprocessing || len(ExtractCorrelatedCols4LogicalPlan(np)) > 0 {
 		er.p, er.err = er.b.buildSemiApply(er.p, np, nil, er.asScalar, v.Not)
 		if er.err != nil || !er.asScalar {
 			return v, true
@@ -949,7 +949,7 @@ func (er *expressionRewriter) handleScalarSubquery(ctx context.Context, v *ast.S
 		return v, true
 	}
 	np = er.b.buildMaxOneRow(np)
-	if len(ExtractCorrelatedCols4LogicalPlan(np)) > 0 {
+	if er.b.disableSubQueryPreprocessing || len(ExtractCorrelatedCols4LogicalPlan(np)) > 0 {
 		er.p = er.b.buildApplyWithJoinType(er.p, np, LeftOuterJoin)
 		if np.Schema().Len() > 1 {
 			newCols := make([]expression.Expression, 0, np.Schema().Len())
diff --git a/planner/core/indexmerge_test.go b/planner/core/indexmerge_test.go
index 9fdcf2f809acb..3bba414fcdb9a 100644
--- a/planner/core/indexmerge_test.go
+++ b/planner/core/indexmerge_test.go
@@ -91,7 +91,7 @@ func (s *testIndexMergeSuite) TestIndexMergePathGeneration(c *C) {
 		stmt, err := s.ParseOneStmt(tc, "", "")
 		c.Assert(err, IsNil, comment)
 		Preprocess(s.ctx, stmt, s.is)
-		builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+		builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 		p, err := builder.Build(ctx, stmt)
 		if err != nil {
 			s.testdata.OnRecord(func() {
diff --git a/planner/core/logical_plan_test.go b/planner/core/logical_plan_test.go
index 03e417de66569..577376b6935ac 100644
--- a/planner/core/logical_plan_test.go
+++ b/planner/core/logical_plan_test.go
@@ -1163,7 +1163,7 @@ func (s *testPlanSuite) TestVisitInfo(c *C) {
 		stmt, err := s.ParseOneStmt(tt.sql, "", "")
 		c.Assert(err, IsNil, comment)
 		Preprocess(s.ctx, stmt, s.is)
-		builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+		builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 		builder.ctx.GetSessionVars().SetHashJoinConcurrency(1)
 		_, err = builder.Build(context.TODO(), stmt)
 		c.Assert(err, IsNil, comment)
@@ -1243,7 +1243,7 @@ func (s *testPlanSuite) TestUnion(c *C) {
 		stmt, err := s.ParseOneStmt(tt, "", "")
 		c.Assert(err, IsNil, comment)
 		Preprocess(s.ctx, stmt, s.is)
-		builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+		builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 		plan, err := builder.Build(ctx, stmt)
 		s.testData.OnRecord(func() {
 			output[i].Err = err != nil
@@ -1275,7 +1275,7 @@ func (s *testPlanSuite) TestTopNPushDown(c *C) {
 		stmt, err := s.ParseOneStmt(tt, "", "")
 		c.Assert(err, IsNil, comment)
 		Preprocess(s.ctx, stmt, s.is)
-		builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+		builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 		p, err := builder.Build(ctx, stmt)
 		c.Assert(err, IsNil)
 		p, err = logicalOptimize(ctx, builder.optFlag, p.(LogicalPlan))
@@ -1349,7 +1349,7 @@ func (s *testPlanSuite) TestOuterJoinEliminator(c *C) {
 		stmt, err := s.ParseOneStmt(tt, "", "")
 		c.Assert(err, IsNil, comment)
 		Preprocess(s.ctx, stmt, s.is)
-		builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+		builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 		p, err := builder.Build(ctx, stmt)
 		c.Assert(err, IsNil)
 		p, err = logicalOptimize(ctx, builder.optFlag, p.(LogicalPlan))
@@ -1385,7 +1385,7 @@ func (s *testPlanSuite) TestSelectView(c *C) {
 		stmt, err := s.ParseOneStmt(tt.sql, "", "")
 		c.Assert(err, IsNil, comment)
 		Preprocess(s.ctx, stmt, s.is)
-		builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+		builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 		p, err := builder.Build(ctx, stmt)
 		c.Assert(err, IsNil)
 		p, err = logicalOptimize(ctx, builder.optFlag, p.(LogicalPlan))
@@ -1466,7 +1466,7 @@ func (s *testPlanSuite) optimize(ctx context.Context, sql string) (PhysicalPlan,
 			return nil, nil, err
 		}
 	}
-	builder, _ := NewPlanBuilder(sctx, s.is, &hint.BlockHintProcessor{})
+	builder, _ := NewPlanBuilder().Init(sctx, s.is, &hint.BlockHintProcessor{})
 	p, err := builder.Build(ctx, stmt)
 	if err != nil {
 		return nil, nil, err
@@ -1548,7 +1548,7 @@ func (s *testPlanSuite) TestSkylinePruning(c *C) {
 		stmt, err := s.ParseOneStmt(tt.sql, "", "")
 		c.Assert(err, IsNil, comment)
 		Preprocess(s.ctx, stmt, s.is)
-		builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+		builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 		p, err := builder.Build(ctx, stmt)
 		if err != nil {
 			c.Assert(err.Error(), Equals, tt.result, comment)
@@ -1649,7 +1649,7 @@ func (s *testPlanSuite) TestUpdateEQCond(c *C) {
 		stmt, err := s.ParseOneStmt(tt.sql, "", "")
 		c.Assert(err, IsNil, comment)
 		Preprocess(s.ctx, stmt, s.is)
-		builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+		builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 		p, err := builder.Build(ctx, stmt)
 		c.Assert(err, IsNil)
 		p, err = logicalOptimize(ctx, builder.optFlag, p.(LogicalPlan))
@@ -1665,7 +1665,7 @@ func (s *testPlanSuite) TestConflictedJoinTypeHints(c *C) {
 	stmt, err := s.ParseOneStmt(sql, "", "")
 	c.Assert(err, IsNil)
 	Preprocess(s.ctx, stmt, s.is)
-	builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+	builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 	p, err := builder.Build(ctx, stmt)
 	c.Assert(err, IsNil)
 	p, err = logicalOptimize(ctx, builder.optFlag, p.(LogicalPlan))
@@ -1685,7 +1685,7 @@ func (s *testPlanSuite) TestSimplyOuterJoinWithOnlyOuterExpr(c *C) {
 	stmt, err := s.ParseOneStmt(sql, "", "")
 	c.Assert(err, IsNil)
 	Preprocess(s.ctx, stmt, s.is)
-	builder, _ := NewPlanBuilder(MockContext(), s.is, &hint.BlockHintProcessor{})
+	builder, _ := NewPlanBuilder().Init(MockContext(), s.is, &hint.BlockHintProcessor{})
 	p, err := builder.Build(ctx, stmt)
 	c.Assert(err, IsNil)
 	p, err = logicalOptimize(ctx, builder.optFlag, p.(LogicalPlan))
diff --git a/planner/core/memtable_predicate_extractor_test.go b/planner/core/memtable_predicate_extractor_test.go
index dc36934d4dc1b..3cc16efe3504d 100644
--- a/planner/core/memtable_predicate_extractor_test.go
+++ b/planner/core/memtable_predicate_extractor_test.go
@@ -62,7 +62,7 @@ func (s *extractorSuite) getLogicalMemTable(c *C, se session.Session, parser *pa
 	c.Assert(err, IsNil)
 
 	ctx := context.Background()
-	builder, _ := plannercore.NewPlanBuilder(se, s.dom.InfoSchema(), &hint.BlockHintProcessor{})
+	builder, _ := plannercore.NewPlanBuilder().Init(se, s.dom.InfoSchema(), &hint.BlockHintProcessor{})
 	plan, err := builder.Build(ctx, stmt)
 	c.Assert(err, IsNil)
 
diff --git a/planner/core/optimizer.go b/planner/core/optimizer.go
index 0af7828ce1bbc..26a03629feb22 100644
--- a/planner/core/optimizer.go
+++ b/planner/core/optimizer.go
@@ -90,7 +90,7 @@ type logicalOptRule interface {
 func BuildLogicalPlan(ctx context.Context, sctx sessionctx.Context, node ast.Node, is infoschema.InfoSchema) (Plan, types.NameSlice, error) {
 	sctx.GetSessionVars().PlanID = 0
 	sctx.GetSessionVars().PlanColumnID = 0
-	builder, _ := NewPlanBuilder(sctx, is, &utilhint.BlockHintProcessor{})
+	builder, _ := NewPlanBuilder().Init(sctx, is, &utilhint.BlockHintProcessor{})
 	p, err := builder.Build(ctx, node)
 	if err != nil {
 		return nil, nil, err
diff --git a/planner/core/planbuilder.go b/planner/core/planbuilder.go
index 4a2b5c0f546f9..f5d87b5b2ea5c 100644
--- a/planner/core/planbuilder.go
+++ b/planner/core/planbuilder.go
@@ -471,6 +471,8 @@ type PlanBuilder struct {
 	// 1. use `inside insert`, `update`, `delete` or `select for update` statement
 	// 2. isolation level is RC
 	isForUpdateRead bool
+	// disableSubQueryPreprocessing indicates whether to pre-process uncorrelated sub-queries in rewriting stage.
+	disableSubQueryPreprocessing bool
 }
 
 type handleColHelper struct {
@@ -571,24 +573,48 @@ func (b *PlanBuilder) popSelectOffset() {
 	b.selectOffset = b.selectOffset[:len(b.selectOffset)-1]
 }
 
-// NewPlanBuilder creates a new PlanBuilder. Return the original PlannerSelectBlockAsName as well, callers decide if
+// PlanBuilderOpt is used to adjust the plan builder.
+type PlanBuilderOpt interface {
+	Apply(builder *PlanBuilder)
+}
+
+// PlanBuilderOptNoExecution means the plan builder should not run any executor during Build().
+type PlanBuilderOptNoExecution struct{}
+
+// Apply implements the interface PlanBuilderOpt.
+func (p PlanBuilderOptNoExecution) Apply(builder *PlanBuilder) {
+	builder.disableSubQueryPreprocessing = true
+}
+
+// NewPlanBuilder creates a new PlanBuilder.
+func NewPlanBuilder(opts ...PlanBuilderOpt) *PlanBuilder {
+	builder := &PlanBuilder{
+		colMapper:           make(map[*ast.ColumnNameExpr]int),
+		handleHelper:        &handleColHelper{id2HandleMapStack: make([]map[int64][]HandleCols, 0)},
+		correlatedAggMapper: make(map[*ast.AggregateFuncExpr]*expression.CorrelatedColumn),
+	}
+	for _, opt := range opts {
+		opt.Apply(builder)
+	}
+	return builder
+}
+
+// Init initialize a PlanBuilder.
+// Return the original PlannerSelectBlockAsName as well, callers decide if
 // PlannerSelectBlockAsName should be restored after using this builder.
-func NewPlanBuilder(sctx sessionctx.Context, is infoschema.InfoSchema, processor *hint.BlockHintProcessor) (*PlanBuilder, []ast.HintTable) {
+func (b *PlanBuilder) Init(sctx sessionctx.Context, is infoschema.InfoSchema, processor *hint.BlockHintProcessor) (*PlanBuilder, []ast.HintTable) {
 	savedBlockNames := sctx.GetSessionVars().PlannerSelectBlockAsName
 	if processor == nil {
 		sctx.GetSessionVars().PlannerSelectBlockAsName = nil
 	} else {
 		sctx.GetSessionVars().PlannerSelectBlockAsName = make([]ast.HintTable, processor.MaxSelectStmtOffset()+1)
 	}
-	return &PlanBuilder{
-		ctx:                 sctx,
-		is:                  is,
-		colMapper:           make(map[*ast.ColumnNameExpr]int),
-		handleHelper:        &handleColHelper{id2HandleMapStack: make([]map[int64][]HandleCols, 0)},
-		hintProcessor:       processor,
-		correlatedAggMapper: make(map[*ast.AggregateFuncExpr]*expression.CorrelatedColumn),
-		isForUpdateRead:     sctx.GetSessionVars().IsPessimisticReadConsistency(),
-	}, savedBlockNames
+
+	b.ctx = sctx
+	b.is = is
+	b.hintProcessor = processor
+	b.isForUpdateRead = sctx.GetSessionVars().IsPessimisticReadConsistency()
+	return b, savedBlockNames
 }
 
 // Build builds the ast node to a Plan.
diff --git a/planner/core/planbuilder_test.go b/planner/core/planbuilder_test.go
index f3da2e6d0dba9..0f9205be76412 100644
--- a/planner/core/planbuilder_test.go
+++ b/planner/core/planbuilder_test.go
@@ -114,7 +114,7 @@ func (s *testPlanBuilderSuite) TestGetPathByIndexName(c *C) {
 }
 
 func (s *testPlanBuilderSuite) TestRewriterPool(c *C) {
-	builder, _ := NewPlanBuilder(MockContext(), nil, &hint.BlockHintProcessor{})
+	builder, _ := NewPlanBuilder().Init(MockContext(), nil, &hint.BlockHintProcessor{})
 
 	// Make sure PlanBuilder.getExpressionRewriter() provides clean rewriter from pool.
 	// First, pick one rewriter from the pool and make it dirty.
@@ -168,7 +168,7 @@ func (s *testPlanBuilderSuite) TestDisableFold(c *C) {
 		stmt := st.(*ast.SelectStmt)
 		expr := stmt.Fields.Fields[0].Expr
 
-		builder, _ := NewPlanBuilder(ctx, nil, &hint.BlockHintProcessor{})
+		builder, _ := NewPlanBuilder().Init(ctx, nil, &hint.BlockHintProcessor{})
 		builder.rewriterCounter++
 		rewriter := builder.getExpressionRewriter(context.TODO(), nil)
 		c.Assert(rewriter, NotNil)
diff --git a/planner/core/prepare_test.go b/planner/core/prepare_test.go
index 8de50601a17b6..49011757276f4 100644
--- a/planner/core/prepare_test.go
+++ b/planner/core/prepare_test.go
@@ -196,7 +196,7 @@ func (s *testPlanSerialSuite) TestPrepareCacheDeferredFunction(c *C) {
 		stmt, err := s.ParseOneStmt(sql1, "", "")
 		c.Check(err, IsNil)
 		is := tk.Se.GetSessionVars().TxnCtx.InfoSchema.(infoschema.InfoSchema)
-		builder, _ := core.NewPlanBuilder(tk.Se, is, &hint.BlockHintProcessor{})
+		builder, _ := core.NewPlanBuilder().Init(tk.Se, is, &hint.BlockHintProcessor{})
 		p, err := builder.Build(ctx, stmt)
 		c.Check(err, IsNil)
 		execPlan, ok := p.(*core.Execute)
diff --git a/planner/core/stats_test.go b/planner/core/stats_test.go
index 6b00782719bb6..811793f4c7f45 100644
--- a/planner/core/stats_test.go
+++ b/planner/core/stats_test.go
@@ -76,7 +76,7 @@ func (s *testStatsSuite) TestGroupNDVs(c *C) {
 		stmt, err := s.ParseOneStmt(tt, "", "")
 		c.Assert(err, IsNil, comment)
 		core.Preprocess(tk.Se, stmt, is)
-		builder, _ := core.NewPlanBuilder(tk.Se, is, &hint.BlockHintProcessor{})
+		builder, _ := core.NewPlanBuilder().Init(tk.Se, is, &hint.BlockHintProcessor{})
 		p, err := builder.Build(ctx, stmt)
 		c.Assert(err, IsNil, comment)
 		p, err = core.LogicalOptimize(ctx, builder.GetOptFlag(), p.(core.LogicalPlan))
diff --git a/planner/optimize.go b/planner/optimize.go
index 06f679f71d199..e02b395f14450 100644
--- a/planner/optimize.go
+++ b/planner/optimize.go
@@ -227,7 +227,7 @@ func optimize(ctx context.Context, sctx sessionctx.Context, node ast.Node, is in
 	sctx.GetSessionVars().PlanColumnID = 0
 	hintProcessor := &hint.BlockHintProcessor{Ctx: sctx}
 	node.Accept(hintProcessor)
-	builder, _ := plannercore.NewPlanBuilder(sctx, is, hintProcessor)
+	builder, _ := plannercore.NewPlanBuilder().Init(sctx, is, hintProcessor)
 
 	// reset fields about rewrite
 	sctx.GetSessionVars().RewritePhaseInfo.Reset()
@@ -420,7 +420,7 @@ func OptimizeExecStmt(ctx context.Context, sctx sessionctx.Context,
 	execAst *ast.ExecuteStmt, is infoschema.InfoSchema) (plannercore.Plan, error) {
 	defer trace.StartRegion(ctx, "Optimize").End()
 	var err error
-	builder, _ := plannercore.NewPlanBuilder(sctx, is, nil)
+	builder, _ := plannercore.NewPlanBuilder().Init(sctx, is, nil)
 	p, err := builder.Build(ctx, execAst)
 	if err != nil {
 		return nil, err