Dynamic replication filters — our wheel will be square!

This is both hilarious and sad. The new MySQL 5.7 milestone release presents a new feature — replication filters are now dynamic. This is a great and long awaited feature, no doubt about it.

In short, for years MySQL slaves could filter the incoming stream of replication events based on the database or table name these events were applicable to. These filters were configured using the my.cnf file (or command-line), in particular with the following variables:
replicate_do_db
replicate_ignore_db
replicate_do_table
replicate_ignore_table
replicate_wild_do_table
replicate_wild_ignore_table
Naturally, users wanted to be able to change the values of these options without having to restart the server. …