Re: like performance w/o wildcards.

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Joseph Shraibman <jks(at)selectacast(dot)net>
Cc: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, pgsql-general(at)postgresql(dot)org
Subject: Re: like performance w/o wildcards.
Date: 2003-08-04 22:35:38
Message-ID: 13480.1060036538@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

Joseph Shraibman <jks(at)selectacast(dot)net> writes:
>> The index is for non-LIKE comparisons, like = and >.
>>
> My point is what is the difference? If the index is done char by char then LIKE ought to
> be able to use the index to find 'F*', no matter what the locale is. What can't you
> figure out what is before/after a given char? Don't you have that information? Don't you
> need it to create the index in the first place?

<yawn> Read the archives. We would love to use locale-sorted indexes
for LIKE, but we *can't*. There are too many bizarre sorting rules.
(Hint: almost no locale does its sorting purely "char by char".)

regards, tom lane

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message scott.marlowe 2003-08-04 22:40:11 Re: [osdldbt-general] Re: [PERFORM] OSDL Database Test Suite 3 is
Previous Message Joseph Shraibman 2003-08-04 22:25:43 Re: like performance w/o wildcards.