From: Shawn Green
Date: June 12 2012 3:42pm
Subject: Re: Minor collation question
List-Archive: http://lists.mysql.com/mysql/227632
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On 6/12/2012 9:37 AM, Johan De Meersman wrote:
> ... but too lazy to look for it myself right now :-p
>
> I'm going to be running into (woot, scheduled problems :-p ) the 5.0 to 5.1 upgrade collation issue where German β is now collated as 's' instead of as 'ss', causing duplicate key errors.
>
> The basic solution is to set the collation to utf8_bin - so far, so good - but I'm wondering wether the table collation impacts only sorting, or wether comparisons will also magically become binary and/or other symptoms might pop up ? I suspect 'yes' based on the primary key issue, but I want to verify.
>

The other tactical move has been to jump 5.1 and upgrade directly from 
5.0 to 5.5 where that problem is resolved.  Sure, it's a bit more work 
(full dump/restore is highly recommended) but it avoids the collation 
bug which exists in all 5.1.x releases.

Yes, collations are used for equality and inequality comparisons, too, 
not just sorting. That's why having alternate spellings ,like the words 
"strasse" and "straβe", will collide within a PK in 5.1 where they will 
not for 5.0 or 5.5 (with the appropriate collation).

Regards,
-- 
Shawn Green
MySQL Principal Technical Support Engineer
Oracle USA, Inc. - Hardware and Software, Engineered to Work Together.
Office: Blountville, TN