Note to self: investigate implementing the Double Write Buffers idea in ActiveMQ. ActiveMQ keeps several indexes into the persistent messages that it’s holding and when ActiveMQ is shutdown ungracefully, we rebuild the indexes from the data logs due to them being in inconsistent state. If your queueing up millions of messages, building those indexes can take a long time.

Double buffering may allow us fix inconistencies in those index and gets us running faster..

activemq, kahadb