Wikimetrics fills up a lot of space on the reports table with this problem:

A recurrent report is created on date X. It then spawns child reports every day from X to NOW. But it never deletes those child records. If those records are deleted, wikimetrics thinks the reports haven't run yet and runs them again. So every once in a while wikimetrics looks to be really slow because it's looking through 2 million records to find your reports and your report results.

We should set the created date of recurrent reports to NOW - 1 MONTH or something like that. And then we should delete old recurrent report child rows. Or find some other better solution, because currently we need to manually clean this up every once in a while.