Re: tsearch2 query

On Thu, 2 Oct 2008, Matthew Terenzio wrote:

> There are less than 20,000 records being searched here, but the query takes
> several minutes.
>
> I know this may not be enough info, but would one suggest I optimize the
> query or put my attention towards other areas.
>
>
> SELECT id,date,headline as head,headline(body,q),rank(vectors,q),timestamp
> FROM stories,to_tsquery('$query') AS q WHERE vectors @@ q ORDER BY $sort
> DESC OFFSET $offset LIMIT 20
>

This is common mistake, use subselect and you'll be happy.

Explanation:

headline() is very cost operation, so in your query you obtain headline()
for *ALL* results, while you need to do this only for 20 of them.
Feel the difference ?

Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83