Re: Standbys, txid_current_snapshot, wraparound
Simon Riggs <simon@2ndquadrant.com>
From: Simon Riggs <simon@2ndQuadrant.com>
To: Marko Kreen <markokr@gmail.com>
Cc: Daniel Farina <daniel@heroku.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Andrey Velikoredchanin <uncleandyv@gmail.com>
Date: 2012-03-28T21:54:58Z
Lists: pgsql-hackers
On Wed, Mar 28, 2012 at 10:24 PM, Simon Riggs <simon@2ndquadrant.com> wrote: > On Wed, Mar 28, 2012 at 9:48 PM, Marko Kreen <markokr@gmail.com> wrote: >> On Fri, Mar 23, 2012 at 08:52:40AM +0000, Simon Riggs wrote: >>> Master pg_controldata - OK txid_current_snapshot() - OK >>> Standby pg_controldata - OK txid_current_snapshot() - lower value >> >> On Skytools list is report about master with slaves, but the >> lower value appears on master too: >> >> http://lists.pgfoundry.org/pipermail/skytools-users/2012-March/001601.html >> >> Cc'd original reporter too. > > Thanks. Am looking. I can't see how this could happen on the master at all. On the standby, it can happen if we skip restartpoints for about a couple of billion xids. Which would be a problem. More on this tomorrow. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services