Question about POSIX Regular Expressions performance on large dataset.

Hi!

I'm analyzing the possibility of using PostgreSQL to store a huge
amount of data (around 1000M records, or so....), and these, even
though are short (each record just have a timestamp, and a string that
is less than 128 characters in length), the strings will be matched
against POSIX Regular Expressions (different regexps, and maybe
complex).

Because I don't have a system large enough to test this here, I have
to ask you (I may borrow a medium-size server, but it would take a
week or more, so I decided to ask here first).  How is the performance
of Regexp matching in PostgreSQL?  Can it use indexes? My guess is:
no, because I don't see a way of generally indexing to match regexp :(
, so, tablescans for this huge dataset.....

What do you think of this?

Sincerely,

Ildefonso Camargo