Tom Lane <tgl@sss.pgh.pa.us> writes:
> "Merlin Moncure" <mmoncure@gmail.com> writes:
>> recent versions of mysql do much better, returning same set in < 20ms.
> Well, since they don't do MVCC they can answer this query from the
> index without going to the heap at all. But that still seems remarkably
> fast for something that has to grovel through 300k index entries.
Are you sure you measured that right? I tried to duplicate this using
mysql 5.0.21, and I see runtimes of 0.45 sec without an index and
0.15 sec with. This compares to psql times around 0.175 sec. Doesn't
look to me like we're hurting all that badly, even without using the
index.
regards, tom lane