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Date: Thu, 22 May 2025 22:56:25 +0200
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Subject: Re: PATCH: jsonpath string methods: lower, upper, initcap, l/r/btrim,
 replace, split_part
To: Robert Haas <robertmhaas@gmail.com>,
 Florents Tselai <florents.tselai@gmail.com>
Cc: Alexander Korotkov <aekorotkov@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>,
 pgsql-hackers <pgsql-hackers@lists.postgresql.org>,
 Andrew Dunstan <andrew@dunslane.net>
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From: Peter Eisentraut <peter@eisentraut.org>
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On 09.05.25 21:50, Robert Haas wrote:
> I always struggle a bit to remember our policy on these issues -- to
> the best of my knowledge, we haven't documented it anywhere, and I
> think we probably should. I believe the way it works is that whenever
> a function depends on the operating system's timestamp or locale
> definitions, we decide it has to be stable, not immutable. We don't
> expect those things to be updated very often, but we know sometimes
> they do get updated.

I don't understand how this discussion got to the conclusion that 
functions that depend on the locale cannot be immutable.  Note that the 
top-level functions lower, upper, and initcap themselves are immutable.