ddl: forbit alter table cache in system db (#29998)

pingcap · Nov 24, 2021 · b57c1e1 · b57c1e1
1 parent 71e64bf
commit b57c1e1
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Showing 3 changed files with 29 additions and 1 deletion.
diff --git a/ddl/db_test.go b/ddl/db_test.go
@@ -5664,6 +5664,30 @@ func (s *testSerialDBSuite) TestSetTableFlashReplica(c *C) {
 	c.Assert(err.Error(), Equals, "the tiflash replica count: 2 should be less than the total tiflash server count: 0")
 }
 
+func (s *testSerialDBSuite) TestForbitCacheTableForSystemTable(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	sysTables := make([]string, 0, 24)
+	memOrSysDB := []string{"MySQL", "INFORMATION_SCHEMA", "PERFORMANCE_SCHEMA", "METRICS_SCHEMA"}
+	for _, db := range memOrSysDB {
+		tk.MustExec("use " + db)
+		tk.Se.Auth(&auth.UserIdentity{Username: "root", Hostname: "%"}, nil, nil)
+		rows := tk.MustQuery("show tables").Rows()
+		for i := 0; i < len(rows); i++ {
+			sysTables = append(sysTables, rows[i][0].(string))
+		}
+		for _, one := range sysTables {
+			_, err := tk.Exec(fmt.Sprintf("alter table `%s` cache", one))
+			if db == "MySQL" {
+				c.Assert(err.Error(), Equals, "[ddl:8200]ALTER table cache for tables in system database is currently unsupported")
+			} else {
+				c.Assert(err.Error(), Equals, fmt.Sprintf("[planner:1142]ALTER command denied to user 'root'@'%%' for table '%s'", strings.ToLower(one)))
+			}
+
+		}
+		sysTables = sysTables[:0]
+	}
+}
+
 func (s *testSerialDBSuite) TestSetTableFlashReplicaForSystemTable(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	sysTables := make([]string, 0, 24)

diff --git a/ddl/ddl_api.go b/ddl/ddl_api.go
@@ -6606,7 +6606,10 @@ func (d *ddl) AlterTableCache(ctx sessionctx.Context, ti ast.Ident) (err error)
 		return nil
 	}
 
-	if t.Meta().TempTableType != model.TempTableNone {
+	// forbit cache table in system database.
+	if util.IsMemOrSysDB(schema.Name.L) {
+		return errors.Trace(errUnsupportedAlterCacheForSysTable)
+	} else if t.Meta().TempTableType != model.TempTableNone {
 		return errors.Trace(ErrOptOnTemporaryTable.GenWithStackByArgs("alter temporary table cache"))
 	}
 

diff --git a/ddl/error.go b/ddl/error.go
@@ -50,6 +50,7 @@ var (
 	errUnsupportedAlterTableWithoutValidation = dbterror.ClassDDL.NewStdErr(mysql.ErrUnsupportedDDLOperation, parser_mysql.Message("ALTER TABLE WITHOUT VALIDATION is currently unsupported", nil))
 	errUnsupportedAlterTableOption            = dbterror.ClassDDL.NewStdErr(mysql.ErrUnsupportedDDLOperation, parser_mysql.Message("This type of ALTER TABLE is currently unsupported", nil))
 	errUnsupportedAlterReplicaForSysTable     = dbterror.ClassDDL.NewStdErr(mysql.ErrUnsupportedDDLOperation, parser_mysql.Message("ALTER table replica for tables in system database is currently unsupported", nil))
+	errUnsupportedAlterCacheForSysTable       = dbterror.ClassDDL.NewStdErr(mysql.ErrUnsupportedDDLOperation, parser_mysql.Message("ALTER table cache for tables in system database is currently unsupported", nil))
 	errBlobKeyWithoutLength                   = dbterror.ClassDDL.NewStd(mysql.ErrBlobKeyWithoutLength)
 	errKeyPart0                               = dbterror.ClassDDL.NewStd(mysql.ErrKeyPart0)
 	errIncorrectPrefixKey                     = dbterror.ClassDDL.NewStd(mysql.ErrWrongSubKey)