From: Tom Lane <tgl@sss.pgh.pa.us>
To: Bruce Momjian <bruce@momjian.us>
cc: Justin Pryzby <pryzby@telsasoft.com>, pgsql-hackers@lists.postgresql.org
Subject: Re: pg_upgrade should truncate/remove its logs before running
In-reply-to: <20211215210916.GC4440@momjian.us>
References: <20211212025017.GN17618@telsasoft.com>
 <20211215210916.GC4440@momjian.us>
Comments: In-reply-to Bruce Momjian <bruce@momjian.us>
	message dated "Wed, 15 Dec 2021 16:09:16 -0500"
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Date: Wed, 15 Dec 2021 16:17:23 -0500
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Bruce Momjian <bruce@momjian.us> writes:
> On Sat, Dec 11, 2021 at 08:50:17PM -0600, Justin Pryzby wrote:
>> If pg_upgrade fails and is re-run, it appends to its logfiles, which is
>> confusing since, if it fails again, it then looks like the original error
>> recurred and wasn't fixed.  The "append" behavior dates back to 717f6d608.

> Uh, the database server doesn't erase its logs on crash/failure, so why
> should pg_upgrade do that?

The server emits enough information so that it's not confusing:
there are timestamps, and there's an identifiable startup line.
pg_upgrade does neither.  If you don't want to truncate as
Justin suggests, you should do that instead.

Personally I like the idea of making a timestamped subdirectory
and dropping all the files in that, because the thing that most
annoys *me* about pg_upgrade is the litter it leaves behind in
$CWD.  A subdirectory would make it far easier to mop up the mess.

			regards, tom lane