Re: like performance w/o wildcards. - Mailing list pgsql-general

From Tom Lane
Subject Re: like performance w/o wildcards.
Date
Msg-id 13480.1060036538@sss.pgh.pa.us
Whole thread Raw
In response to Re: like performance w/o wildcards.  (Joseph Shraibman <jks@selectacast.net>)
Responses Re: like performance w/o wildcards.  (Joseph Shraibman <jks@selectacast.net>)
List pgsql-general
Joseph Shraibman <jks@selectacast.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

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