do not sync persistent store when get a fake position (#397)

* do not sync persistent store when get a fake position

Author: lintanghui

canal/sync.go

@@ -50,7 +50,11 @@ 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 equal zero ,it is a fake rotate event,ignore it.
+		// see https://github.com/mysql/mysql-server/blob/8cc757da3d87bf4a1f07dcfb2d3c96fed3806870/sql/rpl_binlog_sender.cc#L899
+		if ev.Header.LogPos == 0 {
+			continue
+		}
 		savePos = false
 		force = false
 		pos := c.master.Position()