dogpiling

[Piotr Sikora]

> He's referring to a cache stampede, when an item in the proxy cache 
> expires and multiple threads simultaneously try to repopulate it causing 
> load spikes and possible locking conditions.

nginx changes status of expired cache items to "UPDATING" for the period of 
time when it fetches new copies. Combine this with "proxy_cache_use_stale 
updating" and "dogpiling" shouldn't be a problem.

Best regards,
Piotr Sikora < piotr.sikora at frickle.com >