Re: Concurrency

On Mon, 2005-05-09 at 15:18 -0400, Tom Lane wrote:
> Simon Riggs <simon@2ndquadrant.com> writes:
> > On Mon, 2005-05-09 at 12:21 -0500, Kris Kiger wrote:
> >> Quick question.  I lock a table, call it table X, and then issue two
> >> updates on that table.  The two updates are left waiting.  I then unlock
> >> the table.   The two updates go through.  My question is, is there a
> >> predictable way to determine which query will be executed first?
>
> > The lock queue is served in FIFO sequence.
>
> ... usually.  We will promote later arrivals in front of older ones if
> the alternative would be a deadlock (eg, the later one already holds
> some lock that would block the earlier one).

Thats part of deadlock detection? I had thought we just blew one away...

Thanks,

Best Regards, Simon Riggs