I'm making a new ticket for this, in order to allow us to merge LB-230 as soon as possible.

I would like to see a minor improvement to the logging, so that we can tune DUMP_CHUNK_SIZE – right now we have no way to knowing if that setting is good.

Let's go to a single line of output for each user:

[timestamp] dumped <user>, <count> listens, <listens / duration> listens/sec

This way we can play with the DUMP_CHUNK_SIZE and inspect the logs to see how we're doing.