ddl: support alter table auto_increment

ddl/ddl_api.go

@@ -885,6 +885,13 @@ func (d *ddl) AlterTable(ctx context.Context, ident ast.Ident, specs []*ast.Alte
 			err = d.RenameTable(ctx, ident, newIdent)
 		case ast.AlterTableDropPrimaryKey:
 			err = ErrUnsupportedModifyPrimaryKey.GenByArgs("drop")
+		case ast.AlterTableOption:
+			for _, opt := range spec.Options {
+				if opt.Tp == ast.TableOptionAutoIncrement {
+					err = d.RebaseAutoID(ctx, ident, int64(opt.UintValue-1))
+					break
+				}
+			}
 		default:
 			// Nothing to do now.
 		}
@@ -897,6 +904,14 @@ func (d *ddl) AlterTable(ctx context.Context, ident ast.Ident, specs []*ast.Alte
 	return nil
 }
 
+func (d *ddl) RebaseAutoID(ctx context.Context, ident ast.Ident, newBase int64) error {
+	t, err := d.infoHandle.Get().TableByName(ident.Schema, ident.Name)
+	if err != nil {
+		return errors.Trace(infoschema.ErrTableNotExists.GenByArgs(ident.Schema, ident.Name))
+	}
+	return t.RebaseAutoID(ctx, newBase, true)
+}
+
 func checkColumnConstraint(constraints []*ast.ColumnOption) error {
 	for _, constraint := range constraints {
 		switch constraint.Tp {

ddl/ddl_db_test.go

@@ -1676,3 +1676,21 @@ func (s *testDBSuite) TestComment(c *C) {
 
 	s.tk.MustExec("drop table if exists ct, ct1")
 }
+
+func (s *testDBSuite) TestRebaseAutoID(c *C) {
+	s.tk = testkit.NewTestKit(c, s.store)
+	s.tk.MustExec("use " + s.schemaName)
+
+	s.tk.MustExec("drop database if exists tidb;")
+	s.tk.MustExec("create database tidb;")
+	s.tk.MustExec("use tidb;")
+	s.tk.MustExec("create table tidb.test (a int auto_increment primary key, b int);")
+	s.tk.MustExec("insert tidb.test values (null, 1);")
+	s.tk.MustQuery("select * from tidb.test").Check(testkit.Rows("1 1"))
+	s.tk.MustExec("alter table tidb.test auto_increment = 10;")
+	s.tk.MustExec("insert tidb.test values (null, 1);")
+	s.tk.MustQuery("select * from tidb.test").Check(testkit.Rows("1 1", "10 1"))
+	s.tk.MustExec("alter table tidb.test auto_increment = 5;")
+	s.tk.MustExec("insert tidb.test values (null, 1);")
+	s.tk.MustQuery("select * from tidb.test").Check(testkit.Rows("1 1", "10 1", "11 1"))
+}

plan/preprocess.go

@@ -333,13 +333,6 @@ func (p *preprocessor) checkAlterTableGrammar(stmt *ast.AlterTableStmt) {
 			default:
 				// Nothing to do now.
 			}
-		case ast.AlterTableOption:
-			for _, opt := range spec.Options {
-				if opt.Tp == ast.TableOptionAutoIncrement {
-					p.err = ErrAlterAutoID
-					return
-				}
-			}
 		default:
 			// Nothing to do now.
 		}

plan/preprocess_test.go

@@ -75,9 +75,8 @@ func (s *testValidatorSuite) TestValidator(c *C) {
 			errors.New("[schema:1068]Multiple primary key defined")},
 		{"create table t(c1 int not null, c2 int not null, primary key(c1), primary key(c2))", true,
 			errors.New("[schema:1068]Multiple primary key defined")},
-		{"alter table t auto_increment=1", true, errors.New("[autoid:3]No support for setting auto_increment using alter_table")},
-		{"alter table t add column c int auto_increment key, auto_increment=10", true,
-			errors.New("[autoid:3]No support for setting auto_increment using alter_table")},
+		{"alter table t auto_increment=1", true, nil},
+		{"alter table t add column c int auto_increment key, auto_increment=10", true, nil},
 		{"alter table t add column c int auto_increment key", true, nil},
 		{"alter table t add column char4294967295 char(255)", true, nil},
 		{"create table t (c float(53))", true, nil},
@@ -184,6 +183,6 @@ func (s *testValidatorSuite) TestValidator(c *C) {
 		c.Assert(stmts, HasLen, 1)
 		stmt := stmts[0]
 		err = plan.Preprocess(ctx, stmt, is, tt.inPrepare)
-		c.Assert(terror.ErrorEqual(err, tt.err), IsTrue)
+		c.Assert(terror.ErrorEqual(err, tt.err), IsTrue, Commentf("sql: %s", tt.sql))
 	}
 }