fix(canal): handle fake rotate events correctly for MariaDB 11.4

After upgrading to MariaDB 11.4, the canal module stopped detecting row
updates within transactions due to incorrect handling of fake rotate events.
MariaDB 11.4 does not set LogPos for certain events, causing these events
to be ignored. This fix modifies the handling to consider fake rotate events
only for ROTATE_EVENTs with timestamp = 0, aligning with MariaDB and MySQL
documentation.

Author: mefcorvi

canal/sync.go

@@ -47,22 +47,22 @@ func (c *Canal) runSyncBinlog() error {
 		// Update the delay between the Canal and the Master before the handler hooks are called
 		c.updateReplicationDelay(ev)
 
-		// If log pos equals zero then the received event is a fake rotate event and
-		// contains only a name of the next binlog file
-		// See https://github.com/mysql/mysql-server/blob/8e797a5d6eb3a87f16498edcb7261a75897babae/sql/rpl_binlog_sender.h#L235
-		// and https://github.com/mysql/mysql-server/blob/8cc757da3d87bf4a1f07dcfb2d3c96fed3806870/sql/rpl_binlog_sender.cc#L899
-		if ev.Header.LogPos == 0 {
-			switch e := ev.Event.(type) {
-			case *replication.RotateEvent:
+		switch e := ev.Event.(type) {
+		case *replication.RotateEvent:
+			// If the timestamp equals zero, the received rotate event is a fake rotate event
+			// and contains only the name of the next binlog file. Its log position should be
+			// ignored.
+			// See https://github.com/mysql/mysql-server/blob/8e797a5d6eb3a87f16498edcb7261a75897babae/sql/rpl_binlog_sender.h#L235
+			// and https://github.com/mysql/mysql-server/blob/8cc757da3d87bf4a1f07dcfb2d3c96fed3806870/sql/rpl_binlog_sender.cc#L899
+			if ev.Header.Timestamp == 0 {
 				fakeRotateLogName := string(e.NextLogName)
 				c.cfg.Logger.Infof("received fake rotate event, next log name is %s", e.NextLogName)
+
 				if fakeRotateLogName != c.master.Position().Name {
 					c.cfg.Logger.Info("log name changed, the fake rotate event will be handled as a real rotate event")
 				} else {
 					continue
 				}
-			default:
-				continue
 			}
 		}