Text Selectivity Operators in String Types - Mailing list pgsql-hackers

From David E. Wheeler
Subject Text Selectivity Operators in String Types
Date
Msg-id E9527D89-30DD-4569-AFD5-C78D4BFC1071@kineticode.com
Whole thread Raw
Responses Re: Text Selectivity Operators in String Types  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Howdy,

A while back, thanks to feedback from RhodiumToad on #postgresql, I  
added selectivity functions to the citext operators:

CREATE OPERATOR = (    LEFTARG    = CITEXT,    RIGHTARG   = CITEXT,    COMMUTATOR = =,    NEGATOR    = <>,    PROCEDURE
= citext_eq,    RESTRICT   = eqsel,    JOIN       = eqjoinsel,    HASHES,    MERGES
 
);

However, it looks like these might be less than ideal:
  http://www.depesz.com/index.php/2008/08/10/waiting-for-84-case-insensitive-text-citext/
From what depesz sees, the eqsel and eqjoinsel functions might be a  
bit too aggressive in recommending the use of indexes.

So I was wondering, since in CVS HEAD citext is able to identify its  
type category as string, might there also be some way to use the same  
estimator functions in the citext operators as are used for text?

Thanks,

David


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