Q & A

Why OSC doesn't work on RBR

Currently OSC will only work on Facebook's MySQL when the instance is running as binlog-format=ROW. This is mainly because OSC works outside of replication, it depends on changes being recorded through triggers when there're data modifications. However row based replication has its modifications on master written into binary logs instead of triggering it again on slave.

• If we run OSC on a RBR slave, then no changes will be recorded, because RBR events won't trigger triggers.
• When it runs on a RBR master, RBR events that contain changes for shadow table will fail the execution, because slaves don't have the table when OSC is running outside of replication.