From: Tom Lane <tgl@sss.pgh.pa.us>
To: Daniel Gustafsson <daniel@yesql.se>
cc: eugeny@zhuzhnev.com, pgsql-bugs <pgsql-bugs@lists.postgresql.org>,
        Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Subject: Re: BUG #17866: behavior does not match documentation
In-reply-to: <EE5080A8-E4B2-413F-A604-58B1BFAD8942@yesql.se>
References: <17866-18eb70095b1594e2@postgresql.org>
 <1944674.1679596295@sss.pgh.pa.us>
 <EE5080A8-E4B2-413F-A604-58B1BFAD8942@yesql.se>
Comments: In-reply-to Daniel Gustafsson <daniel@yesql.se>
	message dated "Thu, 23 Mar 2023 22:25:49 +0100"
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Date: Thu, 23 Mar 2023 17:54:50 -0400
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Daniel Gustafsson <daniel@yesql.se> writes:
> On 23 Mar 2023, at 19:31, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I wonder if we should rethink that and have these operations strip
>> insignificant trailing zeroes.

> Any app relying on insignificant trailing zeroes seems broken, but the i=
nverse
> can be argued as well.  It's however quite easy to argue for the strippe=
d
> output being more readable though.

It's more readable for sure, and it duplicates what you got in pre-v14
versions, at least textually.  I'm not sure I'd propose back-patching
this, but it feels like a good idea for HEAD.

The argument for the current behavior probably goes like "we're exposing
the actual precision of the value".  But I don't believe that we are;
we're exposing the maximum possible precision.  We have no way to know
how precise the original timestamp or interval input was.  So I don't
think there's much basis for claiming that the result is good to six
fractional digits.

			regards, tom lane