Hi Am 20.02.2014 um 10:19 schrieb Carsten Ziegeler <cziege...@apache.org>:
> Hi, > > as noted in SLING-3400 we have a problem when a resource provider factory > is unregistered and a resource resolver is currently using a provider from > this factory. In that case, that reference is never cleared. > This problem occurs due to long running resource resolvers. > > I looked at solving this issue and my first idea was to simply remove the > reference to the provider if the factory is unregistered. Unfortunately, > this comes with the drawback that we have to keep a reference to all open > resource resolver (contexts) in order to notify them, once a factory is > removed. > Although this is feasible, while implementing it I came to the conclusion > that this is actually the wrong approach: a resource resolver is using / > has used a provider and this one silently disappears. This might cause some > trouble / unexpected behaviour. > > So I rather think, once this happens all resource resolvers need to be > closed and recreated - the easiest way to do this is to unregister and > reregister the resource resolver factory. However, I think simply modifying > the service registration of the resolver factory would be the better option > and should do the trick. This will be expensive since serlvets are registered as ResourceProviders this will cause all ResourceResolverFactory consumers to be "cycled" whenever a servlet is registered and unregistered. I think that is inappropriate overhead. Rather, I think it is perfectly fine to me, that we remove ResourceProvider instances used by ResourceResolver objects: At the end of the day, this is like removing JCR node subtree: A ResourceResolver cannot expect for this to exist for ever. Basically we have two cases: (1) ResourceProvider from ResourceProviderFactory (2) ResourceProvider service IIRC the second case of ResourceProvider services is easy because essentially a ResourceResovler instances share the same ResourceProviderEntry which in turn calls the ResourceProvider. Unregistering the ResourceProvider would just remove the ResourceProvider from the ResourceProviderEntry. For ResourceResourceProviderFactory it is a bit more complicated: Maybe we must keep a collection of ResourceProviderEntry instances which refer to the ResourceProvider instances provided by the ResourceProviderFactory. When the factory is unregistered the respective ResourceProvider instances are removed from the entries. Does that make sense ? Regards Felix > > WDYT? > > Regards > Carsten > -- > Carsten Ziegeler > cziege...@apache.org
