My last session of the day was “MySQL at Twitter – 2015” by 3 engineers at Twitter (Calvin Sun, Inaam Rana, and Anton Kuraev). They mainly use MySQL for Timeline, Social graphs, users, and other uses for internal operations. They use Master-Master replication but mostly Master-Slave. They are running on Twitter WebScale 5.6.23. They went over a lot of their improvements they have put into MySQL5.5. Two of interest were auditing and query throttling.
Some of the changes are not practical for our workloads, but they have ported a lot of 5.7 features back into WebScale 5.6. They showed that in an I/O bound cluster the node upgraded to 5.6 had much fewer page flushes. They are working on a copy of write to improve incremental backups and provide consistent snapshots. They also announced MySQL on Mesos named Mysos. Mesos is a distributed kernel that makes for very large clusters of computers. This looks pretty cool and is worth a deep dive after I get back from conference.
The Copy on Write has the potential to really help the MySQL backup story.