I've poked around, but I cannot get metadata.db to be populated with data. Apparently some r/w cache sits inbetween, and isn't that eager to dump the state. The file got updated after I've added some content to the reader and ran '/etc/init.d/xserver-nodm restart' (obviously), but afterwards, no updates. both file_metadata and application_data tables remain empty.
And answering your earlier question, Iņigo, strace is there