On Wed, May 4, 2011 at 10:32 PM, Gavin Panella <gavin.pane...@canonical.com> wrote: > One common performance killing pattern is dereferencing non-cached > References on a sequence of model objects. A stupid example might be: > > owners = [bug.owner for bug in lots_of_bugs] > > Instead we're learning to write this like: > > owners = bulk.load_related(Person, lots_of_bugs, "ownerID")
I suspect this should be a Storm feature. Something like Bug.owner.load(lots_of_bugs) > One approach to improving this situation could be to forbid (with > code) the use of Reference properties that are not already cached (in > the store cache; this is nothing to do with @cachedproperty). Rather than forbid, we could warnings.warn(). This will break tests, but continue to work live for any untested code paths that sneak through. > Doing this everywhere is not going to fly, at least right now - > there's probably way too much code that would break if we did this - > and sometimes we would want to permit their use - when we're just > looking up a single object for example. Adding a ratchet might help for the broken tests. ie. only raise that warning the 10th time we dereference, resetting the counter in DatabaseLayer.testTearDown(). > Before taking this any further I am interested in your views. Can you > think of places where you could, or could have, used this? Is the > granularity right, or should we be able to restrict just individual > properties, or all properties on a model class? Is the idea okay but > the implementation going about it all wrong? Enforcing this will catch issues, but I can't see how to enforce it without also requiring the bulk load syntax be used for accessing a single item. I suspect this would be an awful lot of fallout in the current code base, and a lot of typing to fix as I don't think we can use a script to migrate the code. -- Stuart Bishop <stu...@stuartbishop.net> http://www.stuartbishop.net/ _______________________________________________ Mailing list: https://launchpad.net/~launchpad-dev Post to : launchpad-dev@lists.launchpad.net Unsubscribe : https://launchpad.net/~launchpad-dev More help : https://help.launchpad.net/ListHelp
