George, Le Jeudi 26 Août 2004 19:58, George Essig a écrit : > Bill Footcow wrote: > > ... > > > I have done a simple request, looking for title or description having > > Postgres inside order by rank and date, like this : > > SELECT a.title, a.id, a.url, to_char(a.r_date, 'DD/MM/YYYY HH24:MI:SS') > > as dt, s.site_name, s.id_site, case when exists (select id_user from > > user_choice u where u.id_site=s.id_site and u.id_user = 1) then 1 else 0 > > end as bookmarked FROM article a, site s > > WHERE s.id_site = a.id_site > > AND idxfti @@ to_tsquery('postgresql') > > ORDER BY rank(idxfti, to_tsquery('postgresql')) DESC, a.r_date DESC; > > > > The request takes about 4 seconds ... I have about 1 400 000 records in > > article and 36 000 records in site table ... it's a Bi-Pentium III 933 > > MHz server with 1 Gb memory ... I'm using Postgresql 7.4.5 > > For me this result is very very slow I really need a quicker result with > > less than 1 second ... > > The next time I call the same request I have got the result in 439 ms ... > > but > > ... > > The first query is slow because the relevant index pages are not cached in > memory. Everyone experiences this. GiST indexes on tsvector columns can > get really big. You have done nothing wrong. When you have a lot of > records, tsearch2 will not run fast without extensive performance tuning. > > Read the following: > > Optimization > http://www.sai.msu.su/~megera/postgres/gist/tsearch/V2/docs/oscon_tsearch2/ >optimization.html > > ...
I have well read many pages about this subject ... but I have not found any thing for the moment to really help me ... What can I do to optimize my PostgreSQL configuration for a special use of Tsearch2 ... I'm a little dispointed looking the Postgresql Russian search engine using Tsearch2 is really quick ... why I can't haev the same result with a bi-pentium III 933 and 1Gb of RAM with the text indexation of 1 500 000 records ? Regards, -- Hervé Piedvache Elma Ingénierie Informatique 6 rue du Faubourg Saint-Honoré F-75008 - Paris - France Pho. 33-144949901 Fax. 33-144949902 ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly