LP:781320 - 5.2.5-99 on CentOS 5.5 x86_64: FederatedX memory leak during SELECTs

We use the FederatedX engine exclusively for SELECTs.

Local (MyISAM) tables are populated with INSERT INTO ... SELECT FROM <Federated table>. Aggregation and other querying is done against the local tables.

Memory is almost always being leaked by the SELECTs. Successive queries usually cause unallocated RAM to be consumed, instead of reusing that which had been already allocated by mysqld. The box eventually starts to page, at which point the instance needs to be restarted.