Re: pg_upgrade if 'postgres' database is dropped

On 28 October 2011 14:28, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Fri, Oct 28, 2011 at 8:12 AM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>> Yes, that would work, but see my summarization email on this.  Using
>> template1 is not a problem for pg_upgrade, it is the modifications to
>> pg_dumpall that are an issue.
>
> I just did a bit of testing on this.  It appears that pg_dumpall, if
> given a cluster containing no postgres database, will happily try to
> connect to template1 instead.  If template1 isn't available either,
> you can use "-l SOMEDBNAME" to specify the name of another database to
> connect to instead.  So there is infinite flexibility there.
>
> But regardless of which database it uses to *generate* the dump, the
> dump itself will *always* contain this, right at the very beginning:
>
> \connect postgres
>
> That line is in fact hard-coded as a literal string in pg_dumpall.c.
> It seems like the easiest fix here might be to just remove that line
> from the dump, because AFAICS it's completely pointless.  During the
> time for which that setting is in effect, we're just restoring
> globals, so it shouldn't matter which database we're connected to;
> only that we have a valid connection.  So trying to switch the
> connection from whatever the user is connected to currently to
> postgres doesn't accomplish anything useful, but it does make it
> possible for dump restoration to unnecessarily fail.

This was the kind of qualm I had with createdb, which I submitted a
patch for earlier this year:
http://archives.postgresql.org/pgsql-hackers/2011-03/msg00999.php

--
Thom Brown
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