We have a 10.2.18 master and 4 slaves with 10.2.18. Because of this bug that I've reported last week (https://jira.mariadb.org/browse/MDEV-17420) we tried to upgrade one of the replicas to 10.3.10 to see if the bug was still there in that version.
After the upgrade, the slave began to sync binary log events from the master, but after a few seconds it stopped with the following errors:
We checked the binary log in the master and does not seem corrupted and the other 3 replicas are working ok (still with 10.2.18). Also the relay log on the slave seems ok.
The slave is stopped with the following status:
We have already tried with RESET SLAVE, clearing relay logs and executing CHANGE MASTER TO again. But the result is the same.
I've dumped the master binary log at that position and, interestingly, slave IO thread stops in a binlog block (master binlog format is MIXED).
The master/slave set that is failing is the main database server for our organization. It has 1.2 TB of data with 38 databases, views, stored procedures, triggers and complex queries.
In the same servers, we have 3 other small sets of master/slaves with the same combination (10.2.18 master and 10.3.10 slaves) and are working perfectly. Of course, these sets are smaller and simpler than the instance that is failing.