May 29, 2019
 Percona Live Open Source Database Conference 2019
  Dieter Adriaenssens

GTIDs were introduced to solve replication problems and improve database consistency.

When, accidentally, transactions occur on a replica, this introduces GTIDs on that replica that don't exist on the master. When, on a master failover, this replica becomes the new master, and the corresponding binlogs of the errant GTIDs are already purged, replication breaks on the replicas of this new master, because those missing GTIDs can't be retrieved from the binlogs of this new master.

This presentation will talk about GTIDs and how to detect errant GTIDs on a replica (before the corresponding binlogs are purged) and how to look at the corresponding transactions in the binlogs. I'll give some examples of transactions that could happen on a replica that didn't originate from a primary node, explain how this is possible and share some tips on how to avoid this.

Basic understanding of MySQL database replication is assumed.



About the Author

Dieter Adriaenssens

Dieter Adriaenssens lives in Belgium where he works as a system administrator and MySQL DBA at Ghent University. He has a background in system administration and web development on a LAMP stack. Over the years he contributed to several Open Source projects and was a phpMyAdmin team member. In his free time Dieter enjoys (rock) climbing.