Andres Freund <andres@2ndquadrant.com> wrote:
> On 2013-11-20 05:59:58 -0800, Kevin Grittner wrote:
>> I don't understand where that would make sense; especially since
>> I thought that a database FREEZE followed by a checkpoint
>> releases old clog space anyway.
>
> It only releases them up to the (cluster wide) xmin horizon. So
> if there are older snapshots or prepared xacts around...
So as long as there are no open transactions or prepared
transactions on the master which started before the release with
the fix is applied, VACUUM FREEZE would be guaranteed to work?
Since I don't see how a non-prepared transaction would be running
from before a minor release upgrade, that just means we have to
make sure there are no prepared transactions from before the
upgrade?
--
Kevin Grittner
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