Little Background:
masters running version 5.6.17-65.0-rel65.0-log no GTID enabled
replicas running version 5.6.29-76.2-log
We are looking to migrate all our servers to GTID. I have setup many of them already (getting ready for migration), basically I have an old master and setup a new slave to point to the master (without GTID). I set SET GLOBAL gtid_deployment_step = ON on the new replica before I sync up the replica using a backup that comes from xtrabackup. This all works fine, database sync’s up and catches up with no errors. I can see the GTID information in the show master status and show slave status information.
What we found was after about a week to 3 weeks…it’s a bit hard to tell when, the GTID information seems to stop being used. The show master status and show slave status both stop showing GTID information. I can check GTID variables using show variables like ‘%version%’ and everything looks OK (except that the gtid_executed is blank which is always blank even on a working server so not sure if this is actually a problem, on a functioning server gtid_purged would have a GTID value)…IE I get:
mysql> show variables like ‘%gtid%’;
±--------------------------------±----------+
| Variable_name | Value |
±--------------------------------±----------+
| binlog_gtid_simple_recovery | OFF |
| enforce_gtid_consistency | ON |
| gtid_deployment_step | ON |
| gtid_executed | |
| gtid_mode | ON |
| gtid_next | AUTOMATIC |
| gtid_owned | |
| gtid_purged | |
| simplified_binlog_gtid_recovery | OFF |
±--------------------------------±----------+
We have rerun the same process on 7 different clusters and the oldest ones (5) seem to have lost GTID usage and the latest ones (2) we sync’ed up are still functioning as expected. I have also looked at the mysql logs and there is no indication of issues. Replication itself seams to work just fine…(the master binlog position on the replica matches the binlog position on the master).
I have looked all over for a bug of this type but so far no hits.
Any ideas or suggestions from you members?
Many thanks,
Andre