Bruno Wolff III <bruno(at)wolff(dot)to> writes:
> Is there a simple way to do something like the following:
> create unique index inst_u_app on inst (lower(host), psport);
> It looks like you can have an index on several columns, but not
> several functions.
The standard answer is to make a custom function that accepts all the
columns and produces a result you can index.
This is sort of an academic "an existence proof is good enough" answer,
but it *is* possible to get the results you want. Making it more
convenient hasn't risen to the top of anyone's to-do list.
regards, tom lane