Size of the Table
22 million rows approximately
I have no experience on large datasets so people with more experience in
this area are going to have to chime in.
My gut feel is 13 seconds for Postgresql to sort through an index of that
size and table is not bad.
you may need to take a look at hardware and postgresql.config settings to
improve the performance for this query
This query is very simple where changing it around or adding index results
massive improvements is not going to help in this case.
the hardware is e5405 dual quad core on a 16GB RAM machine, with 8.3.1
default settings except maximum connections increased...
That could be problem, Postgresql default settings are very
conservative.