Hi, I am using semi-sync replication with the `rpl_semi_sync_master_timeout` set to a very high value to ensure commits aren't committed on the master unless they have been replicated to the slave. However whenever the binlog filename changes the replication stalls indefinitely. A trace of this interaction between the master and the semi-sync slave is here: https://gist.github.com/josephglanville/e87ae96b9be9125427b58cd3a43d5c1e The semi-sync settings I have configured on the master are: rpl_semi_sync_master_wait_point = "AFTER_SYNC" rpl_semi_sync_master_timeout = 18446744073709551615 # effectively infinite as we don't want to fallback to async repl rpl_semi_sync_master_enabled = 1 rpl_semi_sync_master_wait_no_slave = 1 # don't allow writes if slave isn't connected Up until the binlog filename change everything works as expected. Anyone have any ideas on how to fix the problem or is this a bug in semi-sync replication? Joseph.