From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: David Fetter <david@fetter.org>,
        PostgreSQL Development <pgsql-hackers@postgresql.org>
Subject: Re: Finer grain log timestamps
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Mon, 13 Jun 2022 15:55:51 -0400"
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Date: Mon, 13 Jun 2022 16:22:42 -0400
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Robert Haas <robertmhaas@gmail.com> writes:
> On Sun, May 8, 2022 at 4:45 PM David Fetter <david@fetter.org> wrote:
>> Please find attached a patch to change the sub-second granularity of
>> log timestamps from milliseconds to  microseconds.

> Why is this a good idea?

I can imagine that some people would have a use for microsecond
resolution in log files, and I can also imagine that as machines
get faster more people will want that.  As against that, this
will bloat log files by a non-microscopic amount, and it's pretty
likely to break some log-scanning tools too.  It's unclear to me
that that's a tradeoff we should force on everyone.

I think a proposal less likely to have push-back would be to invent
a different log_line_prefix %-escape to produce microseconds.
Sadly, "%u" is already taken, but perhaps we could use "%U"?

A different line of thought is to extend %t to provide a precision
field a la sprintf, so that for example "%.3t" is equivalent to
"%m" and "%.6t" does what David wants, and we won't have to
search for a new escape letter when the day arrives that
somebody wants nanosecond resolution.  The same could be done
with %n, avoiding the need to find a different escape letter
for that.

			regards, tom lane