tsearch2 query
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 $offset LIMIT 20
On Thu, 2 Oct 2008, Matthew Terenzio wrote:
There are less than 20,000 records being searched here, but the query takes
several minutes.I know this may not be enough info, but would one suggest I optimize the
query or put my attention towards other areas.SELECT id,date,headline as head,headline(body,q),rank(vectors,q),timestamp
FROM stories,to_tsquery('$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@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83