Re: Regex query not using index

"Postgres User" <postgres.developer@gmail.com> writes:
> My users are developers and the goal was to accept a simple
> comma-delimited list of string values as a function's input parameter.
>  The function would then parse this input param into a valid regex
> expression.

Why are you fixated on this being a regex?  If you aren't actually
trying to expose regex capabilities to the users, you'll just be having
to suppress a bunch of strange behaviors for special characters.

ISTM that the best solution is to use an array-of-text parameter,
along the lines of

    where name = any (array['Smith', 'Jones', ...])

For what you're doing, you'd not actually want the array[] syntax,
it would look more like

    where name = any ('{Smith,Jones}'::text[])

This should optimize into an indexscan in 8.2 or later.

            regards, tom lane