Re: Regex Query Index question - Mailing list pgsql-general

From Tom Lane
Subject Re: Regex Query Index question
Date
Msg-id 12579.1313102993@sss.pgh.pa.us
Whole thread Raw
In response to Regex Query Index question  (Naoko Reeves <naokoreeves@gmail.com>)
Responses Re: Regex Query Index question  (Naoko Reeves <naokoreeves@gmail.com>)
List pgsql-general
Naoko Reeves <naokoreeves@gmail.com> writes:
> I have query phone number in database as follows:
> [123) 456-7890
> (123) 456-7890

> When I query like this:

> SELECT * FROM phone

> WHERE phone_number ~ ('^\[123' || '[-\s\)]{0,2}' || '456' || '[-\s\)]{0,2}'
> || '7890')

> it use Index but if I query like this (notice first character is
> open parenthesis instead of open square blacket ) :

> SELECT phn_fk_key FROM phn WHERE

> phn_fk_table = 14

> AND llx_decrypt(phn_phone_enc) ~ ('^\(123' || '[-\s\)]{0,2}' || '456' ||
> '[-\s\)]{0,2}' || '7890')

> It doesn't use Index....

Probably it thinks the index isn't selective enough for that case.  How
many entries are there starting with "(123"?

(BTW, I assume you've got standard_conforming_strings turned on, else
there are some other issues with these backslashes ...)

            regards, tom lane

pgsql-general by date:

Previous
From: Marc Munro
Date:
Subject: Re: [HACKERS] Dropping extensions
Next
From: Naoko Reeves
Date:
Subject: Re: Regex Query Index question