MySQL Bugs: #101948: heartbeat is not compatible with local info

Bug #101948	heartbeat is not compatible with local info
Submitted:	10 Dec 2020 8:00	Modified:	31 Dec 2020 12:08
Reporter:	Yan Huang (OCA)	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: Replication	Severity:	S3 (Non-critical)
Version:	5.7.29, 5.7.32	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
There is a next_position field in binlog event header, which is 4 bytes int. 

If the binlog is larger than 4G, the next_position will overflow.

Replication heartbeat will report error "heartbeat is not compatible with local info" when it find the next_position is smaller than current log position.

How to repeat:
1. On master, prepare two large transactions (whose binlog size > 4G), and commit the two at the same time (make sure the large transactions are in the same binlog) 
2. If the first transaction GTID is A:4, and second is A:5, run following commands on slave:

- stop slave; reset slave;
- reset master;
- set global gtid_purged = "A:1-4"
- change master to MASTER_HEARTBEAT_PERIOD = 0.01;
- change master to MASTER_AUTO_POSITION = 1;
- start slave io_thread;

It will make slave start replication from the position after the first large transaction, whose position is larger than 4G. Master will send a Heartbeat on that position, which will cause slave IO thread error.

Suggested fix:
add a next_position_high field in extra_headers of v4 event header, put the high bits in the field.

Hello Yan Huang,

Thank you for the report and feedback.
Verified as described on 5.7.32 build.

Thanks,
Umesh

Related - Bug #101955