Re: Tsearch2 really slower than ilike ?

Oleg,

Le Mercredi 17 Novembre 2004 18:23, Oleg Bartunov a écrit :
> > Sorry but when I do your request I get :
> > # select id_site from site where idx_site_name @@  'livejourn';
> > ERROR:  type " " does not exist
>
> no idea :) btw, what version of postgresql and OS you're running.
> Could you try minimal test - check sql commands from tsearch2 sources,
> some basic queries from tsearch2 documentation, tutorials.
>
> btw, your query should looks like
> select id_site from site_rss where idx_site_name @@ 'livejourn';
> ^^^^^^^^
>
> How did you run your queries at all ? I mean your first message about
> poor tsearch2 performance.

I don't know what happend yesterday ... it's running now ...

You sent me :
zz=# explain analyze select id_site from site_rss where idx_site_name
@@  'livejourn';
                                                             QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------
  Index Scan using ix_idx_site_name on site_rss  (cost=0.00..733.62 rows=184
width=4) (actual time=0.339..39.183 rows=1737 loops=1)
    Index Cond: (idx_site_name @@ '\'livejourn\''::tsquery)
    Filter: (idx_site_name @@ '\'livejourn\''::tsquery)
  Total runtime: 40.997 ms
(4 rows)

>It's really fast ! So, I don't understand your problem.
>I run query on my desktop machine, nothing special.

I get this :
QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------------------------
Index Scan using ix_idx_site_name on site_rss s (cost=0.00..574.19 rows=187
width=24) (actual time=105.097..7157.277 rows=388 loops=1)
Index Cond: (idx_site_name @@ '\'livejourn\''::tsquery)
Filter: (idx_site_name @@ '\'livejourn\''::tsquery)
Total runtime: 7158.576 ms
(4 rows)

With the ilike I get :
QUERY PLAN
------------------------------------------------------------------------------------------------------------
Seq Scan on site_rss s (cost=0.00..8360.23 rows=1 width=24) (actual
time=8.195..879.440 rows=404 loops=1)
Filter: (site_name ~~* '%livejourn%'::text)
Total runtime: 882.600 ms
(3 rows)

I don't know what is your desktop ... but I'm using PostgreSQL 7.4.6, on
Debian Woody with a PC Bi-PIII 933 Mhz and 1 Gb of memory ... the server is
dedicated to this database ... !!

I have no idea !

Regards,

--
Hervé Piedvache

Elma Ingénierie Informatique
6 rue du Faubourg Saint-Honoré
F-75008 - Paris - France
Pho. 33-144949901
Fax. 33-144949902