On Thu, Sep 8, 2011 at 6:46 PM, Robert Haas <robertmh...@gmail.com> wrote: > I'm not convinced it's anywhere near that easy. For one thing, on at > least one big server I'm playing with, memory latency on shared memory > is vastly higher (like >10x!) than on backend-local memory due to NUMA > effects.
I wonder if both the shared mem and non-local memory issue can be circumvented by using a slru like mechanism as a side channel to publish taken snapshots and make concurrent xids available with a sinval/hasmessages like per proc flag in shared memory to notify of migrated snapshots. I'll have to think through the space, locking and performance considerations. That might take a small while though, I just managed to contract the flu and can't really think straight. Sorry to waste your time if this whole approach is completely untenable. It seemed like a interesting topic to sink my teeth in, but in hindsight seems a bit too much for a first try. -- Ants Aasma -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
