Re: Clarification to pg_upgrade docs on reverting to old cluster

On Friday, April 5, 2019 2:26 PM, Magnus Hagander <magnus(at)hagander(dot)net> wrote:

> On Thu, Apr 4, 2019 at 11:14 PM Daniel Gustafsson <daniel(at)yesql(dot)se> wrote:
>
>> Reading the pg_upgrade reference page, I get the feeling that one of the
>> bullets under "Reverting to old cluster" is a bit thin on detail to be helpful
>> to newcomers:
>>
>> "If you ran pg_upgrade with --link, the data files are shared between the
>> old and new cluster. If you started the new cluster, the new server has
>> written to those shared files and it is unsafe to use the old cluster."
>>
>> 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. The attached patch adds
>> a short sentence saying the old cluster should be restored from backups at this
>> point.
>
> Let's have two non-english natives discuss it :),

What could possibly go wrong =)

> 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?

Agreed.

> The third bulletpoint also seems quite complicated really. If we're tweaking these, wouldn't it be better if we split that one in two -- one for "if you ran it without --link", that should reallyi be listed above any of the other options?

Looking at it closer I tend to agree, and updated the patch to split this up in
an attempt to make it a bit clearer for newcomers to pg_upgrade. How about the
attached version?

cheers ./daniel