Thomas Lockhart <lockhart@alumni.caltech.edu> writes:
>> Using the exact same data, and the exact same queries (dbi is cool):
>> MySQL: 0.498u 0.150s 0:02.50 25.6% 10+1652k 0+0io 0pf+0w
>> PgSQL: 0.494u 0.061s 0:19.78 2.7% 10+1532k 0+0io 0pf+0w
>>>> From the 'time' numbers, MySQL is running ~17sec faster, but uses up 23%
>> more CPU to do this...so where is our slowdown?
> I don't remember if you gave details on the sizes of tables, but in
> any case I'm going to guess that you are spending almost all of your
> time in the optimizer.
No --- if he were, it'd be all CPU time, not 2.7% CPU usage. The time's
got to be going into disk accesses. I'm perfectly prepared to blame
the optimizer, but I think it's because of a bad plan not too much time
spent making the plan...
regards, tom lane