Re: Hot standby and b-tree killed items

On Wed, 2008-12-24 at 16:48 +0530, Pavan Deolasee wrote:
> On Wed, Dec 24, 2008 at 4:41 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
> >
> >
> > Greg and Heikki have highlighted in this thread some aspects of btree
> > garbage collection that will increase the chance of queries being
> > cancelled in various circumstances
> 
> Even HOT-prune may lead to frequent query cancellations and unlike
> VACUUM there is no way user can control the frequency of prune
> operations.

The patch does go to some trouble to handle that case, as I'm sure
you've seen. Are you saying that part of the patch is ineffective and
should be removed, or?

Should/could there be a way to control frequency of prune operations? We
could maintain cleanupxmin as a constant minimum distance from xmax, for
example.

Are we saying we should take further measures, as I asked upthread? If
it is a consensus that I take some action, then I will.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support