Re: 8.3 to 8.4 Upgrade issues

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Rod Taylor <rod(dot)taylor(at)gmail(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: 8.3 to 8.4 Upgrade issues
Date: 2010-08-10 17:49:41
Message-ID: 3310.1281462581@sss.pgh.pa.us
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Rod Taylor <rod(dot)taylor(at)gmail(dot)com> writes:
> Does anybody have experience on the cost, if any, of making this change?

> Pg 8.3:
> Encoding: SQL_ASCII
> LC_COLLATE: en_US
> LC_CTYPE: en_US

> Pg 8.4:
> Encoding: SQL_ASCII
> Collation: en_US.UTF-8
> Ctype: en_US.UTF-8

Well, *both* of those settings collections are fundamentally
wrong/bogus; any collation/ctype setting other than "C" is unsafe if
you've got encoding set to SQL_ASCII. But without knowing what your
platform thinks "en_US" means, it's difficult to speculate about what
the difference between them is. I suppose that your libc's default
assumption about encoding is not UTF-8, else these would be equivalent.
If it had been assuming a single-byte encoding, then telling it UTF8
instead could lead to a significant slowdown in strcoll() speed ...
but I would think that would mainly be a problem if you had a lot of
non-ASCII data, and if you did, you'd be having a lot of problems other
than just performance. Have you noticed any change in sorting behavior?

regards, tom lane

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