Re: Freezing without write I/O

On Thu, Jun 6, 2013 at 1:39 PM, Heikki Linnakangas
<hlinnakangas@vmware.com> wrote:
> That will keep OldestXmin from advancing. Which will keep vacuum from
> advancing relfrozenxid/datfrozenxid. Which will first trigger the warnings
> about wrap-around, then stops new XIDs from being generated, and finally a
> forced shutdown.
>
> The forced shutdown will actually happen some time before going beyond 2
> billion XIDs. So it is not possible to have a long-lived transaction, older
> than 2 B XIDs, still live in the system. But let's imagine that you somehow
> bypass the safety mechanism:

Ah, so if you do the epoch in the page header thing or Robert's LSN
trick that I didn't follow then you'll need a new safety check against
this. Since relfrozenxid/datfrozenxid will no longer be necessary.

-- 
greg