Subject: Re: Clarification to pg_upgrade docs on reverting to old cluster
To: Magnus Hagander <magnus@hagander.net>, Daniel Gustafsson <daniel@yesql.se>
Cc: "pgsql-docs@lists.postgresql.org" <pgsql-docs@lists.postgresql.org>
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 <CABUevExh8f947ZP1a=Xki4M_EndakxbWuMOnDdVEH5BRMZC+DA@mail.gmail.com>
From: "Jonathan S. Katz" <jkatz@postgresql.org>
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Message-ID: <d439a7aa-7735-7ed9-8119-3b159a5d7741@postgresql.org>
Date: Fri, 5 Apr 2019 10:15:59 -0400
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From: "Jonathan S. Katz" <jkatz@postgresql.org>
To: Magnus Hagander <magnus@hagander.net>, Daniel Gustafsson <daniel@yesql.se>
Cc: "pgsql-docs@lists.postgresql.org" <pgsql-docs@lists.postgresql.org>
Message-ID: <d439a7aa-7735-7ed9-8119-3b159a5d7741@postgresql.org>
Subject: Re: Clarification to pg_upgrade docs on reverting to old cluster
References: <qtqiv7hI87s_Xvz5ZXHCaH-1-_AZGpIDJowzlRjF3-AbCr3RhSNydM_JCuJ8DE4WZozrtxhIWmyYTbv0syKyfGB6cYMQitp9yN-NZMm-oAo=@yesql.se>
 <CABUevExh8f947ZP1a=Xki4M_EndakxbWuMOnDdVEH5BRMZC+DA@mail.gmail.com>
In-Reply-To: <CABUevExh8f947ZP1a=Xki4M_EndakxbWuMOnDdVEH5BRMZC+DA@mail.gmail.com>

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On 4/5/19 8:26 AM, Magnus Hagander wrote:
>=20
>=20
> On Thu, Apr 4, 2019 at 11:14 PM Daniel Gustafsson <daniel@yesql.se
> <mailto:daniel@yesql.se>> wrote:
>=20
>     Reading the pg_upgrade reference page, I get the feeling that one o=
f the
>     bullets under "Reverting to old cluster" is a bit thin on detail to=

>     be helpful
>     to newcomers:
>=20
>     =C2=A0 =C2=A0 "If you ran pg_upgrade with --link, the data files ar=
e shared
>     between the
>     =C2=A0 =C2=A0 old and new cluster.=C2=A0 If you started the new clu=
ster, the new
>     server has
>     =C2=A0 =C2=A0 written to those shared files and it is unsafe to use=
 the old
>     cluster."
>=20
>     This is perfectly correct, but it fails to provide information on
>     what to do
>     next in case reverting is in fact what the user wants.=C2=A0 The at=
tached
>     patch adds
>     a short sentence saying the old cluster should be restored from
>     backups at this
>     point.
>=20
>=20
> Let's have two non-english natives discuss it :), but wouldn't it sound=

> better with "in this case" than "at this point"? And as a really small
> nitpick, restore from backup, rather than backups?=20

I would go with:

"If you need to restore the old cluster, you will have to do so using
backups that you took prior to the upgrade."

Or if you want to be overly verbose:

"If you need to restore the old cluster, you will have to do so using
backups that you made prior to the upgrade as the --link does not create
a copy of the old cluster files."

Jonathan


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