> I am building a query which uses a clause like "Where doc_description like
> '%keyword%'". I know a normal index won't be of any use here, but since the
> table in question will get fairly big, I do want to use an index.
>
> Can anyone give me some advise on what kind of index I can use here? Or
> shouldn't I use one in this case?
You have to use a proper full text indexing scheme. Investigate
contrib/tsearch2 module in the postgres distribution.
Chirs