Kristian Nielsen <[email protected]> writes： > Here, the second event is just what you suggested, a rotate event containing > the name of the master binlog file. > > But I suppose, the issue is if the slaves relay logs are rotated in the middle > of a master binlog file, due to max_relay_log_size < max_binlog_size or FLUSH > LOGS on the slave? When I tested, I got this:
It indeed would put a rotate event i suggested at relay log head, but not always. if forcely insert a rotate event at relay log head，there would be a redundancy rotate event, which i think not a serious problem though. > One thing to be aware of is that relay log rotates can happen in the middle of > a transaction. So you need to check that this is handled correctly. Also, > there are some special semantics associated with rotate events, some rotate > events are "fake" events generated on the master, and some are synthetic > generated on the slaves, it needs to be all handled correctly. But I think it > should be possible. rotate event’s server id can tell us where it is from (master or slave), so the rotate event i suggested should contain master’ server id. i think there will be no difference to SQL Thread whether it is a fake rotate event or a real rotate event from master or a rotate event i suggested. but SQL Thread have to handle carefully a rotate event during a transaction. > I guess you would need to implement some relay log recovery procedure. Because > in case of crash, the end of the relay log can be corrupt (partial transaction > or event at the end). If we ensure that the SQL thread is also stopped at the > time of recovery, that should be not too hard. i can use xid event to detect a partial transaction, but how to detect a partial event without event checksum, because event checksum only contained in Mariadb 5.5+ and MySQL 5.6+ _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
