Comment 20 for bug 118625

In the log that I have, the first slowdowns are always "built revision graph cache", which tends to indicate that mwhudson is probably on the right track. And indeed, here are the first slowdowns:

1118071120 Start: 05:21:14 End: 05:40:19 Duration: 1144 seconds
    Getting information for RevisionUI (137 secs)
    built revision graph cache (56 secs) Started: 05:37:57

1111767376 Start: 05:21:14 End: 05:40:37 Duration: 1162 seconds
    Getting information for RevisionUI (147 secs)
    built revision graph cache (130 secs) Started: 05:37:58

1120172368 Start: 05:21:14 End: 05:40:47 Duration: 1172 seconds
    Getting information for RevisionUI (169 secs)
    built revision graph cache (111 secs) Started: 05:37:58

1107564880 Start: 05:21:14 End: 05:42:36 Duration: 1281 seconds
    Getting information for AtomUI (25 secs)
    Getting information for AtomUI (31 secs)
    Getting information for RevisionUI (179 secs)
    built revision graph cache (147 secs) Started: 05:37:57

1126476112 Start: 05:21:14 End: 05:42:36 Duration: 1281 seconds
    Getting information for ChangeLogUI (4 secs)
    Getting information for ChangeLogUI (7 secs)
    Getting information for RevisionUI (201 secs)
    built revision graph cache (155 secs) Started: 05:37:58

You can see that they all start roughly simultaneously to build their revision caches. That's a somewhat random time, by the way, since the server started at 05:21:13 in this case.

And after that, no threads ever render, because things are going so slowly. So at the very least, building revision graphs is a performance problem if nothing else. :-)