2011/9/26 Platonides Platonides@gmail.com:
Wouldn't it be able to use the index in rev_id to return it in O(1) ? It takes ages in the toolserver view, but I guess it would be the 428660376 rows it shows in the explain.
No. This works for the MAX(), but not for the COUNT(), where it literally has to count row-by-row. Since there are gaps in the revids, MAX(rev_id) > COUNT(*).
Roan Kattouw (Catrope)