I'm not there to present you a Proof of Concept, I'm only close enough to explain the idea:
- Slave fetches records from Master
- Slave applies the records
- Slave exposes its changes as replication stream to the MySQL Proxy
- MySQL Proxy decodes the RBR records, extracts the Primary Key and updates the content in the memcache server
The MySQL Proxy acts as replication client in this case and exposes the records into LUA land to handle it.
Most of the work will be in decoding the replication stream as the RBR puts some work on the reading side to keep track of the changes.
I'll tell you again when I get there.