The concept of delayed replicated slave is nothing new - Oracle (TM) for example had it for years with the Data Guard. So what is it in the delaying the replicated database slave, how to use it and how to implement it for MySQL - will discuss those topics in the posting.

Most of the replicated MySQL configurations are - one master and several replicated slaves, for the sake of simplicity I'm not going to get into the discussion on shards etc... And in most cases the struggle is to keep the replication up to date.  But there are scenarios  when delaying the replicated slave is actually beneficial.

Delaying MySQL replicated slave is a very valuable "undo" options for the databases. For example if someone accidentally drops one of the MySQL  databases or tables those databases and tables can be easily recovered from the delayed MySQL slave because the drop statement did not get the chance …