bindinfo: set correct default_db for captured bindings (pingcap#15367) (

pingcap#15635)

Co-authored-by: Kenan Yao <cauchy1992@gmail.com>

bindinfo/bind_test.go

@@ -498,6 +498,33 @@ func (s *testSuite) TestCapturePlanBaseline(c *C) {
 	c.Assert(rows[0][1], Equals, "SELECT /*+ USE_INDEX(@`sel_1` `test`.`t` )*/ * FROM `t` WHERE `a`>10")
 }
 
+func (s *testSuite) TestCaptureBaselinesDefaultDB(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	s.cleanBindingEnv(tk)
+	stmtsummary.StmtSummaryByDigestMap.Clear()
+	tk.MustExec(" set @@tidb_capture_plan_baselines = on")
+	defer func() {
+		tk.MustExec(" set @@tidb_capture_plan_baselines = off")
+	}()
+	tk.MustExec("use test")
+	tk.MustExec("drop database if exists spm")
+	tk.MustExec("create database spm")
+	tk.MustExec("create table spm.t(a int, index idx_a(a))")
+	c.Assert(tk.Se.Auth(&auth.UserIdentity{Username: "root", Hostname: "%"}, nil, nil), IsTrue)
+	tk.MustExec("select * from spm.t ignore index(idx_a) where a > 10")
+	tk.MustExec("select * from spm.t ignore index(idx_a) where a > 10")
+	tk.MustExec("admin capture bindings")
+	rows := tk.MustQuery("show global bindings").Rows()
+	c.Assert(len(rows), Equals, 1)
+	// Default DB should be "" when all columns have explicit database name.
+	c.Assert(rows[0][2], Equals, "")
+	c.Assert(rows[0][3], Equals, "using")
+	tk.MustExec("use spm")
+	tk.MustExec("select * from spm.t where a > 10")
+	// Should use TableScan because of the "ignore index" binding.
+	c.Assert(len(tk.Se.GetSessionVars().StmtCtx.IndexNames), Equals, 0)
+}
+
 func (s *testSuite) TestUseMultiplyBindings(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	s.cleanBindingEnv(tk)

bindinfo/handle.go

@@ -37,6 +37,7 @@ import (
 	driver "github.com/pingcap/tidb/types/parser_driver"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/logutil"
+	utilparser "github.com/pingcap/tidb/util/parser"
 	"github.com/pingcap/tidb/util/sqlexec"
 	"github.com/pingcap/tidb/util/stmtsummary"
 	"github.com/pingcap/tidb/util/timeutil"
@@ -529,7 +530,8 @@ func (h *BindHandle) CaptureBaselines() {
 			continue
 		}
 		normalizedSQL, digiest := parser.NormalizeDigest(sqls[i])
-		if r := h.GetBindRecord(digiest, normalizedSQL, schemas[i]); r != nil && r.HasUsingBinding() {
+		dbName := utilparser.GetDefaultDB(stmt, schemas[i])
+		if r := h.GetBindRecord(digiest, normalizedSQL, dbName); r != nil && r.HasUsingBinding() {
 			continue
 		}
 		h.sctx.Lock()
@@ -559,7 +561,7 @@ func (h *BindHandle) CaptureBaselines() {
 			Collation: collation,
 		}
 		// We don't need to pass the `sctx` because they are used to generate hints and we already filled hints in.
-		err = h.AddBindRecord(nil, &BindRecord{OriginalSQL: normalizedSQL, Db: schemas[i], Bindings: []Binding{binding}})
+		err = h.AddBindRecord(nil, &BindRecord{OriginalSQL: normalizedSQL, Db: dbName, Bindings: []Binding{binding}})
 		if err != nil {
 			logutil.BgLogger().Info("capture baseline failed", zap.String("SQL", sqls[i]), zap.Error(err))
 		}

planner/core/planbuilder.go

@@ -46,6 +46,7 @@ import (
 	util2 "github.com/pingcap/tidb/util"
 	"github.com/pingcap/tidb/util/chunk"
 	"github.com/pingcap/tidb/util/logutil"
+	utilparser "github.com/pingcap/tidb/util/parser"
 	"github.com/pingcap/tidb/util/ranger"
 	"github.com/pingcap/tidb/util/set"
 
@@ -558,7 +559,7 @@ 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),
+		Db:           utilparser.GetDefaultDB(v.OriginSel, b.ctx.GetSessionVars().CurrentDB),
 	}
 	if v.HintedSel != nil {
 		p.BindSQL = v.HintedSel.Text()
@@ -575,42 +576,14 @@ 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),
+		Db:           utilparser.GetDefaultDB(v.OriginSel, b.ctx.GetSessionVars().CurrentDB),
 		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 {

util/parser/ast.go

@@ -0,0 +1,47 @@
+// Copyright 2020 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package parser
+
+import (
+	"github.com/pingcap/parser/ast"
+)
+
+// GetDefaultDB checks if all columns in the AST have explicit DBName. If not, return specified DBName.
+func GetDefaultDB(sel ast.StmtNode, dbName string) string {
+	implicitDB := &implicitDatabase{}
+	sel.Accept(implicitDB)
+	if implicitDB.hasImplicit {
+		return dbName
+	}
+	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, i.hasImplicit
+}
+
+func (i *implicitDatabase) Leave(in ast.Node) (out ast.Node, ok bool) {
+	return in, true
+}