Re: 2PC-induced lockup - Mailing list pgsql-hackers

From Hans-Juergen Schoenig
Subject Re: 2PC-induced lockup
Date
Msg-id E4E8FDC4-FF7F-4B89-BE8B-80780A263FB5@cybertec.at
Whole thread Raw
In response to 2PC-induced lockup  (Peter Eisentraut <peter_e@gmx.net>)
List pgsql-hackers
is it good to allow locks on system tables at all?
i am not so sure. have seen some disaster in the past with that. just consider somebody placing ACCESS EXCLUSIVE LOCK on a system table. it is basically denial of service.

best regards,

hans



On Jul 10, 2007, at 3:14 PM, Peter Eisentraut wrote:

The following command sequence appears to lock up the database system:

BEGIN;
LOCK pg_authid;
PREPARE TRANSACTION 'foo';
\q

After that you can't connect anymore, even in single-user mode.  The only way 
I could find is to clear out the pg_twophase directory, but I'm not sure 
whether it is safe to do that.

Should this be prevented somehow, and is there a better recovery path?

-- 
Peter Eisentraut

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