Comment 2 for bug 1221372

This scenario leads to breaking data consistency if you use pt-online-schema-change on a slave, so I consider this as serious issue. Also, regardless of the default binlog_format on the master, client can still set ROW mode per session. So, the tool should abort with error when it detects the slave threads exist. I think though it should be still possible to run pt-osc on slave by enforcing with some additional option, like --force-slave-run or similar.

The same problem seems to not apply to PXC/Galera, as triggers are created on all the nodes.