Re: BUG #5000: Optimizer does not use function-based index for an order by

> Description:        Optimizer does not use function-based index for an order
> by
> Details:
>
> Subject line says it all.

The optimizer makes an educated guess about whether to use indexes or
not. Without more information it's impossible to second-guess it.

You might want to ask on pgsql-general for advice on whether it's
making a good choice and how to influence it. But you'll have to
provide more information such as the actual schema and explain plans
of with and without enable_sort or enable_seqscan disabled.

Also 8.2 came out two years ago, if you're just starting with Postgres
you might as well use 8.4 which has features which will make this
easier -- including the ability to tell the planner how expensive your
function is.

--
greg
http://mit.edu/~gsstark/resume.pdf