On 2013-12-18 13:46:59 +0200, Heikki Linnakangas wrote:
> On 12/18/2013 01:39 PM, Andres Freund wrote:
> >On 2013-12-18 13:07:51 +0200, Heikki Linnakangas wrote:
> >>Here's another idea that doesn't involve SSI:
> >>
> >>At COMMIT, take a new snapshot and check that the assertion still passes
> >>with that snapshot.
> >>I think that would work, and would be simple, although it wouldn't scale too
> >>well.
> >
> >It probably would also be very prone to deadlocks.
>
> Hmm, since this would happen at commit, you would know all the assertions
> that need to be checked at that point. You could check them e.g in Oid order
> to avoid deadlocks.
I think real problem are the lock upgrades, because eventual DML will
have acquired less heavy locks.
Greetings,
Andres Freund
-- Andres Freund http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services