executor: flush statement should trigger implicit commit (#34134)

close pingcap/tidb#34180

executor/simple.go

@@ -1608,8 +1608,20 @@ func (e *SimpleExec) executeDropStats(s *ast.DropStatsStmt) (err error) {
 }
 
 func (e *SimpleExec) autoNewTxn() bool {
+	// Some statements cause an implicit commit
+	// See https://dev.mysql.com/doc/refman/5.7/en/implicit-commit.html
 	switch e.Statement.(type) {
-	case *ast.CreateUserStmt, *ast.AlterUserStmt, *ast.DropUserStmt, *ast.RenameUserStmt:
+	// Data definition language (DDL) statements that define or modify database objects.
+	// (handled in DDL package)
+	// Statements that implicitly use or modify tables in the mysql database.
+	case *ast.CreateUserStmt, *ast.AlterUserStmt, *ast.DropUserStmt, *ast.RenameUserStmt, *ast.RevokeRoleStmt, *ast.GrantRoleStmt:
+		return true
+	// Transaction-control and locking statements.  BEGIN, LOCK TABLES, SET autocommit = 1 (if the value is not already 1), START TRANSACTION, UNLOCK TABLES.
+	// (handled in other place)
+	// Data loading statements. LOAD DATA
+	// (handled in other place)
+	// Administrative statements. TODO: ANALYZE TABLE, CACHE INDEX, CHECK TABLE, FLUSH, LOAD INDEX INTO CACHE, OPTIMIZE TABLE, REPAIR TABLE, RESET (but not RESET PERSIST).
+	case *ast.FlushStmt:
 		return true
 	}
 	return false

executor/simple_test.go

@@ -1049,3 +1049,29 @@ func TestUserWithSetNames(t *testing.T) {
 
 	tk.MustExec("drop user '\xd2\xbb';")
 }
+
+func TestStatementsCauseImplicitCommit(t *testing.T) {
+	// Test some of the implicit commit statements.
+	// See https://dev.mysql.com/doc/refman/5.7/en/implicit-commit.html
+	store, clean := testkit.CreateMockStore(t)
+	defer clean()
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test;")
+	tk.MustExec("create table ic (id int primary key)")
+
+	cases := []string{
+		"create table xx (id int)",
+		"create user 'xx'@'127.0.0.1'",
+		"grant SELECT on test.ic to 'xx'@'127.0.0.1'",
+		"flush privileges",
+		"analyze table ic",
+	}
+	for i, sql := range cases {
+		tk.MustExec("begin")
+		tk.MustExec("insert into ic values (?)", i)
+		tk.MustExec(sql)
+		tk.MustQuery("select * from ic where id = ?", i).Check(testkit.Rows(strconv.FormatInt(int64(i), 10)))
+		// Clean up data
+		tk.MustExec("delete from ic")
+	}
+}