[Zope] Re: login page problem

[Jens Vagelpohl]

On Apr 6, 2005, at 0:52, Chris Withers wrote:

> Dieter Maurer wrote:
>> exUserFolder has built in caching (positive and negative caches),
>
> Dunno what that means, but SUF supports caching via standard 
> RAMCacheManagers or ZSQL method caching.

"negative" caching means that there is a separate cache to cache failed 
user lookups for a while and return a failure immediately instead of 
re-trying the user lookup doing a (possibly expensive) user search in 
the underlying backend.It's a little bit like Squids negative_ttl, 
which is used to specify a duration for caching error responses. The 
negative cache allows the backend to "recover" and/or prevents backend 
overloading because otherwise every failing lookup would hit the 
backend again and again.

jens