Re: tsearch2 in PostgreSQL 8.3?

Trevor Talbot wrote:
> On 8/18/07, Bruce Momjian <bruce@momjian.us> wrote:
> 
> > Remember an expression index can be a user-created function so you can
> > embed whatever you want in your function and just index it's output,
> > just like you would with a trigger creating a separate column.
> 
> Well, you could create a function that returns a tsvector, but how do
> you get that to work with queries?  I've been under the impression the
> expressions need to match (in the normal case, be the same function
> with the same arguments) in order to use the index.

Yes, so you create a function called complex_ts and create the index:
CREATE INDEX ii on x USING GIT(complex_ts(col1, col2))

and in your WHERE clause you do:
WHERE 'a & b' @@ complex_ts(col1, col2)

--  Bruce Momjian  <bruce@momjian.us>          http://momjian.us EnterpriseDB
http://www.enterprisedb.com
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