I am using two MySQL server instances on the same server to filter replication to a third external server. My filter slave is using the blackhole engine as described here: https://dev.mysql.com/doc/refman/5.7/en/blackhole-storage-engine.html
Both master and slave use statement based replication. The documentation says:
Inserts into a BLACKHOLE table do not store any data, but if statement based binary logging is enabled, the SQL statements are logged and replicated to slave servers. This can be useful as a repeater or filter mechanism.
The above statement makes me assume that if I had both of my MySQL instances set to row based replication, nothing would make it to the third, external database. Which kind of makes sense since there are no actual rows in the filtering blackhole database.
However, I have been thinking... Would it not be possible for the filtering middle instance to simply pass on any row based instructions it receives to its own binlog, i.e. would a row-row filtering blackhole setup not work?