We're having issues with the garbage collector unable to keep up with churn caused by needless maven-metadata.xml regeneration.
After increasing some logging levels I've noticed that the YUM addon appears to be responsible for triggering the recalculation of maven-metadata.xml for an entire repository.
i.e. In an hour of logging, recursive maven metadata calculation for the repo always happens immediately after YUM calculation finishes (~every 5 mins).
On disabling automatic yum metadata calculation temporarily (for 15 mins), there were no recursive maven metadata calculations at the root level at all (when, going by the above, at least two would be expected).
This is quite an important issue - as noted at the beginning, because of the resulting churn of maven-metadata.xml files the garbage collector cannot keep up and the binaries table grows indefinitely.