Thread: Full Text Search - Slow on common words
Hi, I have a small web page set up to search within my domain based on keywords. One of the queries is: SELECT page.id ts_rank_cd('{1.0, 1.0, 1.0, 1.0}',contFTI,q) FROM page, to_tsquery('steve') as q WHERE contFTI @@ q My problem is: when someone puts in a commonly seen word, the system slows down and takes a while because of the large amount of data being returned (retrieved from the table) & processed by the rand_cd function. How does everyone else handle something like this? I can only think of 2 possible solutions: - change the query to search for the same terms at least twice in the same document (can I do that?) - limit any searches to x results before ranking & tell the user their search criteria is too generic. Is there a better solution that I am missing? Thanks, Steve -- View this message in context: http://postgresql.1045698.n5.nabble.com/Full-Text-Search-Slow-on-common-words-tp3241060p3241060.html Sent from the PostgreSQL - general mailing list archive at Nabble.com.
On Thu, 2010-10-28 at 12:08 -0700, sub3 wrote:
> Hi,
>
> I have a small web page set up to search within my domain based on keywords.
> One of the queries is:
> SELECT page.id ts_rank_cd('{1.0, 1.0, 1.0, 1.0}',contFTI,q) FROM page,
> to_tsquery('steve') as q WHERE contFTI @@ q
>
> My problem is: when someone puts in a commonly seen word, the system slows
> down and takes a while because of the large amount of data being returned
> (retrieved from the table) & processed by the rand_cd function.
>
> How does everyone else handle something like this? I can only think of 2
> possible solutions:
> - change the query to search for the same terms at least twice in the same
> document (can I do that?)
> - limit any searches to x results before ranking & tell the user their
> search criteria is too generic.
>
> Is there a better solution that I am missing?
>
if the keyword is that common, is it really a keyword? Exclude it.
From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Reid Thompson
Sent: Thursday, October 28, 2010 12:57 PM
To: steve@subwest.com
Cc: Reid Thompson; pgsql-general@postgresql.org
Subject: Re: [GENERAL] Full Text Search - Slow on common words
On Thu, 2010-10-28 at 12:08 -0700, sub3 wrote:
> Hi,
>
> I have a small web page set up to search within my domain based on keywords.
> One of the queries is:
> SELECT page.id ts_rank_cd('{1.0, 1.0, 1.0, 1.0}',contFTI,q) FROM page,
> to_tsquery('steve') as q WHERE contFTI @@ q
>
> My problem is: when someone puts in a commonly seen word, the system slows
> down and takes a while because of the large amount of data being returned
> (retrieved from the table) & processed by the rand_cd function.
>
> How does everyone else handle something like this? I can only think of 2
> possible solutions:
> - change the query to search for the same terms at least twice in the same
> document (can I do that?)
> - limit any searches to x results before ranking & tell the user their
> search criteria is too generic.
>
> Is there a better solution that I am missing?
>
if the keyword is that common, is it really a keyword? Exclude it.
>>
This general idea is called a stopword list. You create a list of words that are so common that searching on them is counter-productive.
http://en.wikipedia.org/wiki/Stop_words
<<