Mark has pointed out that the new maintenance/purgeChangedPages.php script could saturate packet buffers in routers and switches if it sends a very large number of UDP packets in a short period of time. The consequence of this would be that some unknown number of packets are silently discarded due to buffer overflow.
A suggested solution is to insert a small artificial delay before sending each packet. Brandon suggested that a 10ms should be more than enough to prevent buffer overflows. With that rate limit in place we would effectively throttle the HTCP packet output to 100/s (360,000/hr). It's estimated that a 10K-item purge would take ~17 minutes of wall clock time to complete and a 150K list would take 25 minutes .