drop read-only transactions support

Author: shogo82148

connection_go18.go

@@ -48,18 +48,15 @@ func (mc *mysqlConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver
 	if sql.IsolationLevel(opts.Isolation) != sql.LevelDefault {
 		return nil, errors.New("mysql: isolation levels not supported")
 	}
+	if opts.ReadOnly {
+		return nil, errors.New("mysql: read-only transactions not supported")
+	}
 
 	if err := mc.watchCancel(ctx); err != nil {
 		return nil, err
 	}
 
-	var err error
-	var tx driver.Tx
-	if opts.ReadOnly {
-		tx, err = mc.beginReadOnly()
-	} else {
-		tx, err = mc.Begin()
-	}
+	tx, err := mc.Begin()
 	mc.finish()
 	if err != nil {
 		return nil, err
@@ -74,20 +71,6 @@ func (mc *mysqlConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver
 	return tx, err
 }
 
-func (mc *mysqlConn) beginReadOnly() (driver.Tx, error) {
-	if mc.isBroken() {
-		errLog.Print(ErrInvalidConn)
-		return nil, driver.ErrBadConn
-	}
-	// https://dev.mysql.com/doc/refman/5.7/en/innodb-performance-ro-txn.html
-	err := mc.exec("START TRANSACTION READ ONLY")
-	if err != nil {
-		return nil, err
-	}
-
-	return &mysqlTx{mc}, nil
-}
-
 func (mc *mysqlConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
 	dargs, err := namedValueToValue(args)
 	if err != nil {

driver_go18_test.go

@@ -466,41 +466,3 @@ func TestContextCancelBegin(t *testing.T) {
 		}
 	})
 }
-
-func TestContextBeginReadOnly(t *testing.T) {
-	runTests(t, dsn, func(dbt *DBTest) {
-		dbt.mustExec("CREATE TABLE test (v INTEGER)")
-		ctx, cancel := context.WithCancel(context.Background())
-		defer cancel()
-
-		tx, err := dbt.db.BeginTx(ctx, &sql.TxOptions{
-			ReadOnly: true,
-		})
-		if _, ok := err.(*MySQLError); ok {
-			dbt.Skip("It seems that your MySQL does not support READ ONLY transactions")
-			return
-		} else if err != nil {
-			dbt.Fatal(err)
-		}
-
-		// INSERT queries fail in a READ ONLY transaction.
-		_, err = tx.ExecContext(ctx, "INSERT INTO test VALUES (1)")
-		if _, ok := err.(*MySQLError); !ok {
-			dbt.Errorf("expected MySQLError, got %v", err)
-		}
-
-		// SELECT queries can be executed.
-		var v int
-		row := tx.QueryRowContext(ctx, "SELECT COUNT(*) FROM test")
-		if err := row.Scan(&v); err != nil {
-			dbt.Fatal(err)
-		}
-		if v != 0 {
-			dbt.Errorf("expected val to be 0, got %d", v)
-		}
-
-		if err := tx.Commit(); err != nil {
-			dbt.Fatal(err)
-		}
-	})
-}