On Fri, Aug 12, 2011 at 9:33 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
> Yes, they would still need to talk. But the good news is that they
> only actually need to talk once per checkpoint cycle so we can buffer
> them to a certain extent in shared memory to remove the worst part of
> such contention.
Yeah, some kind of special-purpose communication method between the
cleaning scan and the checkpoint process might help, if the lock
contention turns out to be a problem in practice. Then again, maybe
I'm overthinking things: there's zero sign in any profiling I've done
that BgWriterCommLock is even mildly contended, so even worrying about
it at this point might be a waste of time.
> Checkpointing needs a little more time in its diary to receive those
> messages than it has right now, so there's no easy route.
Yeah.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
