Re: Indexes on individual columns of composite primary key

"Dan Halbert" <halbert@halwitz.org> writes:
> I have a table with four columns. Three of those columns are defined
> as the composite primary key. Does it make sense to create indexes on
> any or all of those three columns individually for performance
> reasons?

Please see
http://www.postgresql.org/docs/9.0/static/indexes.html
particularly sections 11.3 and 11.5.

            regards, tom lane