On Fri, May 27, 2011 at 04:55:07PM -0400, Robert Haas wrote: > When a strong lock is taken or released, we have to increment or > decrement strong_lock_counts[fasthashpartition]. Here's the question: > is that atomic? In other words, suppose that strong_lock_counts[42] > starts out at 0, and two backends both do ++strong_lock_counts[42]. > Are we guaranteed to end up with "2" in that memory location or might > we unluckily end up with "1"? I think the latter is possible... and > some guard is needed to make sure that doesn't happen.
Yeah: what Tom said. Guard it with a spinlock? Given that the backend is about to (or did earlier) go off and acquire dozens or hundreds of LWLocks, it doesn't seem like an area begging for early optimization. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
