When a server shuts down and restarts, its MEMORY (HEAP) tables become empty. As of MySQL 4.0.18, the master replicates this effect to slaves as follows: The first time that the master uses each MEMORY table after startup, it logs an event that notifies slaves that the table must be emptied by writing a DELETE statement for that table to the binary log. See Section 13.4, “The MEMORY (HEAP) Storage Engine”, for more information about MEMORY tables.