Re: pgsql: doc: mention dependency on collation libraries

On Sat, Jul 2, 2016 at 06:02:12PM +0200, Christoph Berg wrote:
> Re: Bruce Momjian 2016-07-02 <20160702155517(dot)GD18610(at)momjian(dot)us>
> > > Shouldn't this mention that OS upgrades are a possible problem as
> > > well? We've seen the de_DE.UTF-8 ordering break in RHEL 5->6, and
> > > again in 6->7. (5 and 7 are compatible.) The problematic strings were
> > > "999" and "9-9-9".
> >
> > Yes, we can do that. Do you have suggested wording? I was not sure how
> > to tell people anything related to collation versions.
>
> How about simply this: ?
>
> Non<literal>C</> and and non-<literal>POSIX</> locales rely on the
> operating system's collation library for character set ordering.
> This controls the ordering of keys stored in indexes. For this
> eason,
> a cluster cannot switch to an incompatible collation library
> ersion,
> either through
>
> + operating system upgrade,
>
> snapshot restore, binary streaming replication, or
> <application>pg_upgrade</> run.

OK, good point. I was more focused on cluster moves than an OS change.
How is the attached patch?

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Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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