https://issues.apache.org/jira/browse/AMQ-3162 - ActiveMQ checkpoint worker makes unnecessary repeated calls to Journal.getFileMap(), leading to excessive memory usage applied variation of the patch with thanks. Now make one call to find the current set of referenced files.
activemq/trunk/activemq-core/src/main/java/org/apache/activemq/store/kahadb/MessageDatabase.java