Date: Tue, 28 Jun 2016 18:50:15 -0400
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Bruce Momjian <bruce@momjian.us>,
	PostgreSQL-documentation <pgsql-docs@postgresql.org>
Subject: Re: Pg_upgrade and collation
Message-ID: <20160628225015.GA82106@alvherre.pgsql>
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Peter Geoghegan wrote:

> The best argument for ICU is the evidently lax attitude that the glibc
> people have towards the correctness and consistency of their
> collations:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1320356#c3
> 
> Here, Carlos O'Donnell, a glic committer, says "Regarding (b), the
> collations in glibc may change from build to build depending on
> changes in the algorithms or locales. You cannot rely on the collation
> stay the same once the process exits (nor can you rely upon it via a
> shared memory mapping to another process sorting strings in memory)".
> Frankly, we have no excuse for not heeding his warning.
> 
> I'm not annoyed at the glibc people for taking this position. There
> is, quite simply, a misalignment of incentives. For the glibc people,
> the assumption is that any problem with collations leads only to
> slight annoyance from end users, as when the GUI produces subtly wrong
> ordering. Whereas, for us, any inconsistency is an extremely serious
> problem. Here we have the maintainers of glibc telling us that they
> feel like it's okay that that can happen at any time. Surely that
> isn't good enough.

Uhmm.  Until now I saw all this ICU thing as having fringe benefit on
strange platforms only, but it is seeming more and more like we need to
take it seriously.  I'm not prepared to spend effort on it myself,
though.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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