bindinfo: set default db for bindings correctly (pingcap#14077)

Author: alivxxx

bindinfo/bind_test.go

@@ -603,3 +603,26 @@ func (s *testSuite) TestDefaultSessionVars(c *C) {
 		"tidb_evolve_plan_baselines off",
 		"tidb_use_plan_baselines on"))
 }
+
+func (s *testSuite) TestDefaultDB(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	s.cleanBindingEnv(tk)
+	tk.MustExec("use test")
+	tk.MustExec("create table t(a int, b int, index idx(a))")
+	tk.MustExec("create global binding for select * from test.t using select * from test.t use index(idx)")
+	tk.MustExec("use mysql")
+	tk.MustQuery("select * from test.t")
+	// Even in another database, we could still use the bindings.
+	c.Assert(tk.Se.GetSessionVars().StmtCtx.IndexNames[0], Equals, "t:idx")
+	tk.MustExec("drop global binding for select * from test.t")
+	tk.MustQuery("show global bindings").Check(testkit.Rows())
+
+	tk.MustExec("use test")
+	tk.MustExec("create session binding for select * from test.t using select * from test.t use index(idx)")
+	tk.MustExec("use mysql")
+	tk.MustQuery("select * from test.t")
+	// Even in another database, we could still use the bindings.
+	c.Assert(tk.Se.GetSessionVars().StmtCtx.IndexNames[0], Equals, "t:idx")
+	tk.MustExec("drop session binding for select * from test.t")
+	tk.MustQuery("show session bindings").Check(testkit.Rows())
+}

executor/bind.go

@@ -34,6 +34,7 @@ type SQLBindExec struct {
 	bindSQL      string
 	charset      string
 	collation    string
+	db           string
 	isGlobal     bool
 	bindAst      ast.StmtNode
 }
@@ -69,9 +70,9 @@ func (e *SQLBindExec) dropSQLBind() error {
 	}
 	if !e.isGlobal {
 		handle := e.ctx.Value(bindinfo.SessionBindInfoKeyType).(*bindinfo.SessionHandle)
-		return handle.DropBindRecord(e.normdOrigSQL, e.ctx.GetSessionVars().CurrentDB, bindInfo)
+		return handle.DropBindRecord(e.normdOrigSQL, e.db, bindInfo)
 	}
-	return domain.GetDomain(e.ctx).BindHandle().DropBindRecord(e.normdOrigSQL, e.ctx.GetSessionVars().CurrentDB, bindInfo)
+	return domain.GetDomain(e.ctx).BindHandle().DropBindRecord(e.normdOrigSQL, e.db, bindInfo)
 }
 
 func (e *SQLBindExec) createSQLBind() error {
@@ -83,7 +84,7 @@ func (e *SQLBindExec) createSQLBind() error {
 	}
 	record := &bindinfo.BindRecord{
 		OriginalSQL: e.normdOrigSQL,
-		Db:          e.ctx.GetSessionVars().CurrentDB,
+		Db:          e.db,
 		Bindings:    []bindinfo.Binding{bindInfo},
 	}
 	if !e.isGlobal {

executor/builder.go

@@ -2535,6 +2535,7 @@ func (b *executorBuilder) buildSQLBindExec(v *plannercore.SQLBindPlan) Executor
 		bindSQL:      v.BindSQL,
 		charset:      v.Charset,
 		collation:    v.Collation,
+		db:           v.Db,
 		isGlobal:     v.IsGlobal,
 		bindAst:      v.BindStmt,
 	}

planner/core/common_plans.go

@@ -498,6 +498,7 @@ type SQLBindPlan struct {
 	BindSQL      string
 	IsGlobal     bool
 	BindStmt     ast.StmtNode
+	Db           string
 	Charset      string
 	Collation    string
 }

planner/core/planbuilder.go

@@ -524,6 +524,7 @@ func (b *PlanBuilder) buildDropBindPlan(v *ast.DropBindingStmt) (Plan, error) {
 		SQLBindOp:    OpSQLBindDrop,
 		NormdOrigSQL: parser.Normalize(v.OriginSel.Text()),
 		IsGlobal:     v.GlobalScope,
+		Db:           getDefaultDB(b.ctx, v.OriginSel),
 	}
 	if v.HintedSel != nil {
 		p.BindSQL = v.HintedSel.Text()
@@ -540,13 +541,42 @@ func (b *PlanBuilder) buildCreateBindPlan(v *ast.CreateBindingStmt) (Plan, error
 		BindSQL:      v.HintedSel.Text(),
 		IsGlobal:     v.GlobalScope,
 		BindStmt:     v.HintedSel,
+		Db:           getDefaultDB(b.ctx, v.OriginSel),
 		Charset:      charSet,
 		Collation:    collation,
 	}
 	b.visitInfo = appendVisitInfo(b.visitInfo, mysql.SuperPriv, "", "", "", nil)
 	return p, nil
 }
 
+func getDefaultDB(ctx sessionctx.Context, sel ast.StmtNode) string {
+	implicitDB := &implicitDatabase{}
+	sel.Accept(implicitDB)
+	if implicitDB.hasImplicit {
+		return ctx.GetSessionVars().CurrentDB
+	}
+	return ""
+}
+
+type implicitDatabase struct {
+	hasImplicit bool
+}
+
+func (i *implicitDatabase) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
+	switch x := in.(type) {
+	case *ast.TableName:
+		if x.Schema.L == "" {
+			i.hasImplicit = true
+		}
+		return in, true
+	}
+	return in, false
+}
+
+func (i *implicitDatabase) Leave(in ast.Node) (out ast.Node, ok bool) {
+	return in, true
+}
+
 // detectSelectAgg detects an aggregate function or GROUP BY clause.
 func (b *PlanBuilder) detectSelectAgg(sel *ast.SelectStmt) bool {
 	if sel.GroupBy != nil {

planner/core/preprocess.go

@@ -123,6 +123,7 @@ func (p *preprocessor) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
 		EraseLastSemicolon(node.OriginSel)
 		EraseLastSemicolon(node.HintedSel)
 		p.checkBindGrammar(node.OriginSel, node.HintedSel)
+		return in, true
 	case *ast.DropBindingStmt:
 		EraseLastSemicolon(node.OriginSel)
 		if node.HintedSel != nil {

planner/optimize.go

@@ -189,6 +189,9 @@ func getBindRecord(ctx sessionctx.Context, stmt ast.StmtNode) (*bindinfo.BindRec
 	}
 	sessionHandle := ctx.Value(bindinfo.SessionBindInfoKeyType).(*bindinfo.SessionHandle)
 	bindRecord := sessionHandle.GetBindRecord(normalizedSQL, ctx.GetSessionVars().CurrentDB)
+	if bindRecord == nil {
+		bindRecord = sessionHandle.GetBindRecord(normalizedSQL, "")
+	}
 	if bindRecord != nil {
 		if bindRecord.HasUsingBinding() {
 			return bindRecord, metrics.ScopeSession