Message-ID: <54CBB4AB.1090805@commandprompt.com>
Date: Fri, 30 Jan 2015 08:43:23 -0800
From: "Joshua D. Drake" <jd@commandprompt.com>
Organization: Command Prompt, Inc.
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To: Bruce Momjian <bruce@momjian.us>, Robert Haas <robertmhaas@gmail.com>
CC: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: tablespaces inside $PGDATA considered harmful
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 <CA+TgmobZLyLU8tFCbMqbjMWB6t+=ERaDo820uQEJCVAQK_Paow@mail.gmail.com>
 <20150130161928.GB20744@momjian.us>
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On 01/30/2015 08:19 AM, Bruce Momjian wrote:
>
> On Fri, Jan 30, 2015 at 11:12:43AM -0500, Robert Haas wrote:
>> I think everyone who has read this mailing list for a while is
>> probably already aware of this problem.  When you create a tablespace
>> somewhere inside the data directory, weird things happen. If you
>> pg_upgrade and then incautiously run the delete_old_cluster.sh script
>> thus created, you will blow away large chunks of your data.[1]  If you
>
> pg_upgrade doesn't create the deletion script in this case, and warns
> the user:
>
>          Could not create a script to delete the old cluster's data
>          files because user-defined tablespaces exist in the old cluster
>          directory.  The old cluster's contents must be deleted manually.
>
>> In the short term, I favor just adding a warning, so that people get
>> some clue that they are doing something that might be a bad idea.  In
>> the long term, we might want to do more.  Thoughts?
>
> Yes, good idea.

Uhm, wouldn't it be a rather simple patch to say:

if tablespace_create() in $PGDATA:
   ERROR!

?

I mean yes a warning is good but it is after the fact, the tablespace is 
already created. We know that tablespaces in $PGDATA are a bad idea, why 
not protect the user?

JD


>


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