Performance on the IMAP server had been getting progressively worse following a recent Cyrus upgrade. A periodic maintenence job on the IMAP server was taking an increasing amount of time to run, and was driving the system load progressively higher. One-minute load averages of over 70 were starting to show up with regularity, and the problem was getting more and more noticable.

A fix was eventually found. Can you guess when it was put in place?