diff --git a/ddl/ddl.go b/ddl/ddl.go
index 01a2e76df0..aff01f4202 100644
--- a/ddl/ddl.go
+++ b/ddl/ddl.go
@@ -368,7 +368,8 @@ func (d *ddl) buildTableInfo(tableName model.CIStr, cols []*column.Col, constrai
 
 func (d *ddl) CreateTable(ctx context.Context, ident table.Ident, colDefs []*coldef.ColumnDef, constraints []*coldef.TableConstraint) (err error) {
 	is := d.GetInformationSchema()
-	if !is.SchemaExists(ident.Schema) {
+	schema, ok := is.SchemaByName(ident.Schema)
+	if !ok {
 		return errors.Trace(qerror.ErrDatabaseNotExist)
 	}
 	if is.TableExists(ident.Schema, ident.Name) {
@@ -400,7 +401,13 @@ func (d *ddl) CreateTable(ctx context.Context, ident table.Ident, colDefs []*col
 			return errors.Trace(err)
 		}
 
-		err = d.updateInfoSchema(ident.Schema, tbInfo, txn, true)
+		var b []byte
+		b, err = json.Marshal(tbInfo)
+		if err != nil {
+			return errors.Trace(err)
+		}
+
+		err = txn.CreateTable(schema.ID, tbInfo.ID, b)
 		return errors.Trace(err)
 	})
 
@@ -413,9 +420,12 @@ func (d *ddl) CreateTable(ctx context.Context, ident table.Ident, colDefs []*col
 func (d *ddl) AlterTable(ctx context.Context, ident table.Ident, specs []*AlterSpecification) (err error) {
 	// Get database and table.
 	is := d.GetInformationSchema()
-	if !is.SchemaExists(ident.Schema) {
+
+	schema, ok := is.SchemaByName(ident.Schema)
+	if !ok {
 		return errors.Trace(qerror.ErrDatabaseNotExist)
 	}
+
 	tbl, err := is.TableByName(ident.Schema, ident.Name)
 	if err != nil {
 		return errors.Trace(err)
@@ -423,7 +433,7 @@ func (d *ddl) AlterTable(ctx context.Context, ident table.Ident, specs []*AlterS
 	for _, spec := range specs {
 		switch spec.Action {
 		case AlterAddColumn:
-			if err := d.addColumn(ctx, ident.Schema, tbl, spec, is.SchemaMetaVersion()); err != nil {
+			if err := d.addColumn(ctx, schema, tbl, spec, is.SchemaMetaVersion()); err != nil {
 				return errors.Trace(err)
 			}
 		default:
@@ -435,7 +445,7 @@ func (d *ddl) AlterTable(ctx context.Context, ident table.Ident, specs []*AlterS
 }
 
 // Add a column into table
-func (d *ddl) addColumn(ctx context.Context, schema model.CIStr, tbl table.Table, spec *AlterSpecification, schemaMetaVersion int64) error {
+func (d *ddl) addColumn(ctx context.Context, schema *model.DBInfo, tbl table.Table, spec *AlterSpecification, schemaMetaVersion int64) error {
 	// Find position
 	cols := tbl.Cols()
 	position := len(cols)
@@ -497,7 +507,8 @@ func (d *ddl) addColumn(ctx context.Context, schema model.CIStr, tbl table.Table
 		if err != nil {
 			return errors.Trace(err)
 		}
-		err = d.updateInfoSchema(schema, tb.Meta(), txn, false)
+
+		err = d.updateTableInfo(schema, tb.Meta(), txn)
 		return errors.Trace(err)
 	})
 	if d.onDDLChange != nil {
@@ -543,38 +554,24 @@ func updateOldRows(ctx context.Context, t *tables.Table, col *column.Col) error
 // DropTable will proceed even if some table in the list does not exists.
 func (d *ddl) DropTable(ctx context.Context, ti table.Ident) (err error) {
 	is := d.GetInformationSchema()
+	schema, ok := is.SchemaByName(ti.Schema)
+	if !ok {
+		return errors.Trace(qerror.ErrDatabaseNotExist)
+	}
+
 	tb, err := is.TableByName(ti.Schema, ti.Name)
 	if err != nil {
 		return errors.Trace(err)
 	}
-	// update InfoSchema before delete all the table data.
-	clonedInfo := is.Clone()
 
 	err = d.meta.RunInNewTxn(false, func(txn *meta.TMeta) error {
 		err := d.verifySchemaMetaVersion(txn, is.SchemaMetaVersion())
 		if err != nil {
 			return errors.Trace(err)
 		}
-		for _, info := range clonedInfo {
-			if info.Name == ti.Schema {
-				var newTableInfos []*model.TableInfo
-				// append other tables.
-				var tableID int64
-				for _, tbInfo := range info.Tables {
-					if tbInfo.Name.L != ti.Name.L {
-						newTableInfos = append(newTableInfos, tbInfo)
-					} else {
-						tableID = tbInfo.ID
-					}
-				}
-				info.Tables = newTableInfos
-				err = txn.DropTable(info.ID, tableID)
-				if err != nil {
-					return errors.Trace(err)
-				}
-			}
-		}
-		return nil
+
+		err = txn.DropTable(schema.ID, tb.Meta().ID)
+		return errors.Trace(err)
 	})
 	if d.onDDLChange != nil {
 		err = d.onDDLChange(err)
@@ -610,6 +607,11 @@ func (d *ddl) deleteTableData(ctx context.Context, t table.Table) error {
 
 func (d *ddl) CreateIndex(ctx context.Context, ti table.Ident, unique bool, indexName model.CIStr, idxColNames []*coldef.IndexColName) error {
 	is := d.infoHandle.Get()
+	schema, ok := is.SchemaByName(ti.Schema)
+	if !ok {
+		return errors.Trace(qerror.ErrDatabaseNotExist)
+	}
+
 	t, err := is.TableByName(ti.Schema, ti.Name)
 	if err != nil {
 		return errors.Trace(err)
@@ -664,7 +666,8 @@ func (d *ddl) CreateIndex(ctx context.Context, ti table.Ident, unique bool, inde
 		if err != nil {
 			return errors.Trace(err)
 		}
-		err = d.updateInfoSchema(ti.Schema, tbInfo, txn, false)
+
+		err = d.updateTableInfo(schema, tbInfo, txn)
 		return errors.Trace(err)
 	})
 	if d.onDDLChange != nil {
@@ -735,37 +738,11 @@ func (d *ddl) DropIndex(ctx context.Context, schema, tableName, indexNmae model.
 	return nil
 }
 
-func (d *ddl) updateInfoSchema(schema model.CIStr, tbInfo *model.TableInfo, txn *meta.TMeta, create bool) error {
-	is := d.GetInformationSchema()
-	clonedInfo := is.Clone()
-	for _, info := range clonedInfo {
-		if info.Name == schema {
-			var match bool
-			for i := range info.Tables {
-				if info.Tables[i].Name == tbInfo.Name {
-					info.Tables[i] = tbInfo
-					match = true
-				}
-			}
-			if !match {
-				info.Tables = append(info.Tables, tbInfo)
-			}
-
-			b, err := json.Marshal(tbInfo)
-			if err != nil {
-				return errors.Trace(err)
-			}
-
-			if create {
-				err = txn.CreateTable(info.ID, tbInfo.ID, b)
-			} else {
-				err = txn.UpdateTable(info.ID, tbInfo.ID, b)
-			}
-
-			if err != nil {
-				return errors.Trace(err)
-			}
-		}
+func (d *ddl) updateTableInfo(schema *model.DBInfo, tbInfo *model.TableInfo, txn *meta.TMeta) error {
+	b, err := json.Marshal(tbInfo)
+	if err != nil {
+		return errors.Trace(err)
 	}
-	return nil
+
+	return txn.UpdateTable(schema.ID, tbInfo.ID, b)
 }