Skip site navigation (1) Skip section navigation (2)

Re: Help with Query Tuning

From: tv(at)fuzzy(dot)cz
To: "Adarsh Sharma" <adarsh(dot)sharma(at)orkash(dot)com>
Cc: tv(at)fuzzy(dot)cz, pgsql-performance(at)postgresql(dot)org
Subject: Re: Help with Query Tuning
Date: 2011-03-18 15:30:19
Message-ID: 4527c38f24af40c40594d001e09a2724.squirrel@sq.gransy.com (view raw or flat)
Thread:
Lists: pgsql-performance
> Thanks , it works now .. :-)
>
> Here is the output :
>
> pdc_uima=# SELECT count(*)  from page_content WHERE publishing_date like
> '%2010%' and
> pdc_uima-# content_language='en' and content is not null and
> isprocessable = 1 and
> pdc_uima-# to_tsvector('english',content) @@
> to_tsquery('english','Mujahid' || ' | '
> pdc_uima(# || 'jihad' || ' | ' || 'Militant' || ' | ' || 'fedayeen' || ' |
> '
> pdc_uima(# || 'insurgent' || ' | ' || 'terrORist' || ' | ' || 'cadre' ||
> ' | '
> pdc_uima(# || 'civilians' || ' | ' || 'police' || ' | ' || 'cops' ||
> 'crpf' || ' | '
> pdc_uima(# || 'defence' || ' | ' || 'dsf' || ' | ' || 'ssb' );
>
>  count
> --------
>  137193
> (1 row)
>
> Time: 195441.894 ms
>
>
> But my original query is to use AND also i.e

Hi, just replace "AND" and "OR" (used with LIKE operator) for "&" and "|"
(used with to_tsquery).

So this

(content like '%Militant%' OR content like '%jihad%') AND (content like
'%kill%' OR content like '%injure%')

becomes

to_tsvector('english',content) @@ to_tsquery('english', '(Militant |
jihad) & (kill | injure)')

BTW it seems you somehow believe you'll get exactly the same result from
those two queries (LIKE vs. tsearch) - that's false expectation. I believe
the fulltext query is much better and more appropriate in this case, just
don't expect the same results.

regards
Tomas


In response to

pgsql-performance by date

Next:From: Claudio FreireDate: 2011-03-18 16:02:40
Subject: Re: Request for feedback on hardware for a new database server
Previous:From: Claudio FreireDate: 2011-03-18 15:26:20
Subject: Re: Disabling nested loops - worst case performance

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group