From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
cc: Doug Doole <ddoole@salesforce.com>, Craig Ringer <craig@2ndquadrant.com>,
        pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: ICU integration
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Comments: In-reply-to Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
	message dated "Wed, 07 Sep 2016 08:53:22 -0400"
Date: Thu, 08 Sep 2016 11:16:00 -0400
Message-ID: <3006.1473347760@sss.pgh.pa.us>
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Peter Eisentraut <peter.eisentraut@2ndquadrant.com> writes:
> On 9/6/16 1:40 PM, Doug Doole wrote:
>> We carried the ICU version numbers around on our collation and locale
>> IDs (such as fr_FR%icu36) . The database would load multiple versions of
>> the ICU library so that something created with ICU 3.6 would always be
>> processed with ICU 3.6. This avoided the problems of trying to change
>> the rules on the user. (We'd always intended to provide tooling to allow
>> the user to move an existing object up to a newer version of ICU, but we
>> never got around to doing it.) In the code, this meant we were
>> explicitly calling the versioned API so that we could keep the calls
>> straight.

> I understand that in principle, but I don't see operating system
> providers shipping a bunch of ICU versions to facilitate that.  They
> will usually ship one.

I agree with that estimate, and I would further venture that even if we
wanted to bundle ICU into our tarballs, distributors would rip it out
again on security grounds.  I am dead certain Red Hat would do so; less
sure that other vendors have similar policies, but it seems likely.
They don't want to have to fix security bugs in more than one place.

This is a problem, if ICU won't guarantee cross-version compatibility,
because it destroys the argument that moving to ICU would offer us
collation behavior stability.

			regards, tom lane


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