infoschema: fix compatibility of auto_increment column value of INFORMATION_SCHEMA.TABLES (#10207)

ddl/ddl_api.go

@@ -1702,15 +1702,6 @@ func handleTableOptions(options []*ast.TableOption, tbInfo *model.TableInfo) err
 	return nil
 }
 
-func hasAutoIncrementColumn(tbInfo *model.TableInfo) (bool, string) {
-	for _, col := range tbInfo.Columns {
-		if mysql.HasAutoIncrementFlag(col.Flag) {
-			return true, col.Name.L
-		}
-	}
-	return false, ""
-}
-
 // isIgnorableSpec checks if the spec type is ignorable.
 // Some specs are parsed by ignored. This is for compatibility.
 func isIgnorableSpec(tp ast.AlterTableType) bool {

ddl/generated_column.go

@@ -18,6 +18,7 @@ import (
 	"github.com/pingcap/parser/ast"
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/tidb/expression"
+	"github.com/pingcap/tidb/infoschema"
 	"github.com/pingcap/tidb/table"
 )
 
@@ -238,7 +239,7 @@ func checkIndexOrStored(tbl table.Table, oldCol, newCol *table.Column) error {
 // checkAutoIncrementRef checks if an generated column depends on an auto-increment column and raises an error if so.
 // See https://dev.mysql.com/doc/refman/5.7/en/create-table-generated-columns.html for details.
 func checkAutoIncrementRef(name string, dependencies map[string]struct{}, tbInfo *model.TableInfo) error {
-	exists, autoIncrementColumn := hasAutoIncrementColumn(tbInfo)
+	exists, autoIncrementColumn := infoschema.HasAutoIncrementColumn(tbInfo)
 	if exists {
 		if _, found := dependencies[autoIncrementColumn]; found {
 			return ErrGeneratedColumnRefAutoInc.GenWithStackByArgs(name)

executor/show_test.go

@@ -267,7 +267,7 @@ func (s *testSuite2) TestShow2(c *C) {
 	tk.Se.Auth(&auth.UserIdentity{Username: "root", Hostname: "192.168.0.1", AuthUsername: "root", AuthHostname: "%"}, nil, []byte("012345678901234567890"))
 
 	r := tk.MustQuery("show table status from test like 't'")
-	r.Check(testkit.Rows(fmt.Sprintf("t InnoDB 10 Compact 0 0 0 0 0 0 0 %s <nil> <nil> utf8mb4_bin   注释", createTime)))
+	r.Check(testkit.Rows(fmt.Sprintf("t InnoDB 10 Compact 0 0 0 0 0 0 <nil> %s <nil> <nil> utf8mb4_bin   注释", createTime)))
 
 	tk.MustQuery("show databases like 'test'").Check(testkit.Rows("test"))
 
@@ -346,7 +346,7 @@ func (s *testSuite2) TestUnprivilegedShow(c *C) {
 	c.Assert(err, IsNil)
 	createTime := model.TSConvert2Time(tblInfo.Meta().UpdateTS).Format("2006-01-02 15:04:05")
 
-	tk.MustQuery("show table status from testshow").Check(testkit.Rows(fmt.Sprintf("t1 InnoDB 10 Compact 0 0 0 0 0 0 0 %s <nil> <nil> utf8mb4_bin   ", createTime)))
+	tk.MustQuery("show table status from testshow").Check(testkit.Rows(fmt.Sprintf("t1 InnoDB 10 Compact 0 0 0 0 0 0 <nil> %s <nil> <nil> utf8mb4_bin   ", createTime)))
 
 }
 

infoschema/infoschema.go

@@ -388,3 +388,13 @@ func IsMemoryDB(dbName string) bool {
 	}
 	return false
 }
+
+// HasAutoIncrementColumn checks whether the table has auto_increment columns, if so, return true and the column name.
+func HasAutoIncrementColumn(tbInfo *model.TableInfo) (bool, string) {
+	for _, col := range tbInfo.Columns {
+		if mysql.HasAutoIncrementFlag(col.Flag) {
+			return true, col.Name.L
+		}
+	}
+	return false, ""
+}

infoschema/tables.go

@@ -1072,26 +1072,12 @@ func (c *statsCache) get(ctx sessionctx.Context) (map[int64]uint64, map[tableHis
 }
 
 func getAutoIncrementID(ctx sessionctx.Context, schema *model.DBInfo, tblInfo *model.TableInfo) (int64, error) {
-	hasAutoIncID := false
-	for _, col := range tblInfo.Cols() {
-		if mysql.HasAutoIncrementFlag(col.Flag) {
-			hasAutoIncID = true
-			break
-		}
-	}
-	autoIncID := tblInfo.AutoIncID
-	if hasAutoIncID {
-		is := ctx.GetSessionVars().TxnCtx.InfoSchema.(InfoSchema)
-		tbl, err := is.TableByName(schema.Name, tblInfo.Name)
-		if err != nil {
-			return 0, err
-		}
-		autoIncID, err = tbl.Allocator(ctx).NextGlobalAutoID(tblInfo.ID)
-		if err != nil {
-			return 0, err
-		}
+	is := ctx.GetSessionVars().TxnCtx.InfoSchema.(InfoSchema)
+	tbl, err := is.TableByName(schema.Name, tblInfo.Name)
+	if err != nil {
+		return 0, err
 	}
-	return autoIncID, nil
+	return tbl.Allocator(ctx).Base() + 1, nil
 }
 
 func dataForViews(ctx sessionctx.Context, schemas []*model.DBInfo) ([][]types.Datum, error) {
@@ -1162,10 +1148,15 @@ func dataForTables(ctx sessionctx.Context, schemas []*model.DBInfo) ([][]types.D
 				if table.GetPartitionInfo() != nil {
 					createOptions = "partitioned"
 				}
-				autoIncID, err := getAutoIncrementID(ctx, schema, table)
-				if err != nil {
-					return nil, err
+				var autoIncID interface{}
+				hasAutoIncID, _ := HasAutoIncrementColumn(table)
+				if hasAutoIncID {
+					autoIncID, err = getAutoIncrementID(ctx, schema, table)
+					if err != nil {
+						return nil, err
+					}
 				}
+
 				rowCount := tableRowsMap[table.ID]
 				dataLength, indexLength := getDataAndIndexLength(table, rowCount, colLengthMap)
 				avgRowLength := uint64(0)

infoschema/tables_test.go

@@ -84,7 +84,21 @@ func (s *testTableSuite) TestInfoschemaFieldValue(c *C) {
 		testkit.Rows("1"))
 	tk.MustExec("insert into t(c, d) values(1, 1)")
 	tk.MustQuery("select auto_increment from information_schema.tables where table_name='t'").Check(
-		testkit.Rows("30002"))
+		testkit.Rows("2"))
+
+	tk.MustQuery("show create table t").Check(
+		testkit.Rows("" +
+			"t CREATE TABLE `t` (\n" +
+			"  `c` int(11) NOT NULL AUTO_INCREMENT,\n" +
+			"  `d` int(11) DEFAULT NULL,\n" +
+			"  PRIMARY KEY (`c`)\n" +
+			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin AUTO_INCREMENT=30002"))
+
+	// Test auto_increment for table without auto_increment column
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t (d int)")
+	tk.MustQuery("select auto_increment from information_schema.tables where table_name='t'").Check(
+		testkit.Rows("<nil>"))
 
 	tk.MustExec("create user xxx")
 	tk.MustExec("flush privileges")