+ # Using the (log_namespace, log_title, log_timestamp) index with a
+ # range scan (LIKE) on the first two parts, instead of simple equality,
+ # makes it unusable for sorting. Sorted retrieval using another index
+ # would be possible, but then we might have to scan arbitrarily many
+ # nodes of that index. Therefore, we need to avoid this if $wgMiserMode
+ # is on.
+ #
+ # This is not a problem with simple title matches, because then we can
+ # use the page_time index. That should have no more than a few hundred
+ # log entries for even the busiest pages, so it can be safely scanned
+ # in full to satisfy an impossible condition on user or similar.