From: Tom Lane <tgl@sss.pgh.pa.us>
To: Magnus Hagander <magnus@hagander.net>
cc: Jehan-Guillaume de Rorthais <jgdr@dalibo.com>,
        Robert Haas <robertmhaas@gmail.com>,
        Thomas Munro <thomas.munro@gmail.com>,
        "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: when the startup process doesn't
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Comments: In-reply-to Magnus Hagander <magnus@hagander.net>
	message dated "Tue, 20 Apr 2021 19:32:33 +0200"
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Date: Tue, 20 Apr 2021 14:23:08 -0400
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Magnus Hagander <magnus@hagander.net> writes:
> On Tue, Apr 20, 2021 at 5:17 PM Jehan-Guillaume de Rorthais
> <jgdr@dalibo.com> wrote:
>> Two another options:
>> 1. if this is limited to local access only, outside of the log entries,=
 the
>> status of the startup could be updated in the controldata file as well.=
 This
>> would allows to watch it without tail-grep'ing logs using eg. pg_contro=
ldata.

> I think doing so in controldata would definitely make things
> complicated for no real reason. Plus controldata has a fixed size (and
> has to have), whereas something like this would probably want more
> variation than that makes easy.

Also, given that pg_control is as critical a bit of data as we have,
we really don't want to be writing it more often than we absolutely
have to.

> There could be a "startup.status" file I guess which would basically
> contain the last line of what would otherwise be in the log. But if it
> remains a textfile, I'm not sure what the gain is -- you'll just have
> to have the dba look in more places than one to find it? It's not like
> there's likely to be much other data written to the log during these
> times?

Yeah, once you are talking about dumping stuff in a file, it's not
clear how that's better than progress-messages-in-the-log.  People
already have a lot of tooling for looking at the postmaster log.

I think the point of Robert's other proposal is to allow remote
checks of the restart's progress, so local files aren't much of
a substitute anyway.

			regards, tom lane