On Wed, Aug 4, 2010 at 7:33 PM, Stuart Bishop <[email protected]> wrote: > On Wed, Aug 4, 2010 at 9:46 AM, Robert Collins > <[email protected]> wrote: > >> Doing this will immediately close a half-dozen bugs, and focus our >> timeout and performance efforts closer to the actual source of our >> problems. > > Which bugs? The only open ones I'm aware of are feature requests which > I don't think are on anyone's radar to address.
As Martin says, milestone and bugs pages are caching inappropriately. https://bugs.edge.launchpad.net/launchpad/+bug/601051 was originally filed in a pretty general way, got refreshed today. The 'hot bugs' list in a bug context is cached and is jarring (because a common thing to do with a hot bug is to triage it). https://bugs.edge.launchpad.net/malone/+bug/602936 This bug proposes using memcached to address cold cache problems by preloading a lot of batch sizes into it (not a great strategy IMO). https://bugs.edge.launchpad.net/rosetta/+bug/534203 > I'm not sure why turning the facility off will help peoples focus - > memcached was never about stopping timeouts and this has been > repeatedly stressed. That message and developer actions are mismatched. > Using the facility will slow down initial loads, > and may improve the median page load time. It won't fix timeouts. It > may reduce the frequency of timeouts. The memcached infrastructure is > about improving scalability and overall performance, and throwing away > our 24% hit rate seems rather pointless (better rate than I was > expecting actually, but I guess the places it is being used have been > specifically targeted). The same rationales for turning off would be > applied to turning off Squid, which fills pretty much the same role > but more so by caching 100% of our unauthorized access. Caching anonymous stuff is rather easier, because anonymous queries can't create a situation with stale data - if the same user has a logged in and an unlogged in account they'll detect the difference, but not otherwise. > Turning it off is also rather problematic for foundations scalability > and performance work - it is the most likely replacement for OAuth > nonce and Session storage. So, turning it off may be over-broad; removing it where it is being abused is a more accurate way of stating my intention; I'd be happy if we turned it off before the rollout, landed a patch to rollback the inappropriate uses, and then turned it back on for appropriate uses. I certainly don't want to impede scalability and performance work. Using memcache for that does raise some concerns though: wouldn't a system outage of memcache (like say, a kernel vulnerability forcing a reboot) cause all users to have to log in again? We can take this to a different thread. >> In the future, I would like to be able to turn memcached back on in a >> more scaling role, which is what it is designed for and great at. -Rob _______________________________________________ Mailing list: https://launchpad.net/~launchpad-dev Post to : [email protected] Unsubscribe : https://launchpad.net/~launchpad-dev More help : https://help.launchpad.net/ListHelp
