Inserts, deletes, updates, and invalidates, if I remember correctly.
On Thu, Jul 30, 2009 at 5:33 PM, Michael Gentry<mgen...@masslight.net> wrote: > Hi Tobias, > > I've not used the cache synchronization before, but I was under the > impression that the main overhead is when inserts/updates/deletes are > done, not when selects are done. When you do an insert/update/delete, > that information must be broadcast, but selects do not. I'm sure > someone will correct me if I am wrong on this. :-) > > mrg > > > On Thu, Jul 30, 2009 at 5:23 PM, Tobias > Schoessler<tobias.schoess...@gmail.com> wrote: >> So thank you for all the suggestions. The solution we finally ended up with >> was the one Mike actually suggested intitially. We got our multicast ip, >> dropped the latest Jgroups.jar into both webapps lib directories, selected >> Jgroups as the Syncronisation mechanism in the cayenne modeller, used the >> default jgroups udp.xml config file patched with our multicast ip address >> and 'snapp' the contexts were synchronized. Very satisfying - Cayenne >> rocks.! :) >> >> Before this I went down the route of trying to make cayenne use the global >> JVM scope to store the shared cache. I moved the cayenne.jar up on the >> tomcat shared lib directory, out of the two web app lib folders. This did >> not work out well, I got stuck at the point where one web app worked fine >> the other one threw class cast exception on the mapping objects saying it >> cannot cast the types on itself. I assume this is due to the fact that both >> webapps had their own copies of the mapping classes. I tried moving them up >> into the shared tomcat lib aswell, but then they could not see the web app >> specific classes anymore. So anyway I am happy with our Jgroups solution >> now. >> >> The documentation reads lthis setup has some overhead. Does anybody have >> experience/numbers how much performance you loose when using jgroups >> syncronised caches compared to local cache? >> >> thanks again everyone. >> >> On Thu, Jul 30, 2009 at 10:47 AM, Tobias Schoessler < >> tobias.schoess...@gmail.com> wrote: >> >>> Thanks everyone for the posts. >>> >>> @Mike, I am still not convinced that using the Remote Notification Feature >>> is really nessecary here. After all, there seems to be a JVM shared between >>> webapps in Tomcat and the article posted seems to proof that there is a >>> possiblity to share information between the webapps on a JVM level. So I >>> think that using Remote Notification, which I understand to be designed for >>> Cross JVM notification creates too much overhead. >>> >>> You mentioned the possibility of sharing the DataContext between the >>> webapps. I think I have to explore this possibility first, as this would >>> have less overhead compared to the notification based solution. >>> Currently I am using the >>> org.objectstyle.cayenne.conf.ServletUtil.getSessionContext(request.getSession()) >>> to obtain my DataContexts per request. >>> If I could change the scope the DataContexts are stored to cross web app >>> scope instead of session scope I could share the DataContexts between the >>> two web apps. Assuming that I can setup the two webapps to share the same >>> session Ids as described in the article. >>> >>> This might be a no go for me as the two contexts use different >>> authentication realms - I have to check this. But even then wouldn't it be >>> possbile to configure the cayenne shared cache to use this cross web context >>> scope for its shared cache. Then I could use >>> org.objectstyle.cayenne.conf.ServletUtil.getSessionContext(session) in the >>> two web apps transparently and cayenne would refresh the DataContext from >>> this shared cache in the background. Could somebody point me to where this >>> shared cayenne cache is configured to have its scope? I assume it uses JVM >>> static scope? >>> >>> @Malcolm, thanks for suggesting this alternative. If I understand you >>> correctly you suggest to switch off the cayenne cache alltogether and use >>> the jsptag based caching of the OScache project? The problem with this is >>> that not all my responses are generated from jsptags. I have many ajax >>> requests generating json responses without bothering the jsp container. >>> >>> Tobias >>> >>> >>> On Thu, Jul 30, 2009 at 3:00 AM, Malcolm Edgar >>> <malcolm.ed...@gmail.com>wrote: >>> >>>> You can also use OSCache with Cayenne and have the cached queries >>>> expire frequently, i.e. after 30 seconds >>>> >>>> regards Malcolm Edgar >>>> >>>> On Thu, Jul 30, 2009 at 6:36 AM, Mike Kienenberger<mkien...@gmail.com> >>>> wrote: >>>> > Before you make your own custom solution, you might want to read up on >>>> > Javagroup. It might not be a problem to use it in your environment. >>>> > >>>> > The main page starts off with this: >>>> > >>>> > http://www.jgroups.org/ >>>> > ================================== >>>> > JGroups is a toolkit for reliable multicast communication. >>>> > (Note that this doesn't necessarily mean IP Multicast, JGroups can >>>> > also use transports such as TCP). >>>> > >>>> > [...] >>>> > >>>> > JGroups comes with a number of protocols (but anyone can write their >>>> > own), for example >>>> > * Transport protocols: UDP (IP Multicast), TCP, JMS >>>> > >>>> > ================================== >>>> > >>>> > So even if the TCP version doesn't do what you need, you might find it >>>> > easier to write your own Jgroup protocol than to write your own >>>> > cayenne event bridge. It's more likely to be documented and there >>>> > will be more examples/end users to ask questions of. There might even >>>> > be a tomcat shared session protocol out there somewhere. >>>> > >>>> > >>>> > On Wed, Jul 29, 2009 at 4:16 PM, Tobias >>>> > Schoessler<tobias.schoess...@gmail.com> wrote: >>>> >> well i am reading this from the documentation: >>>> >> >>>> >> "... At the minimum, JMS setup requires a JMS server running, and >>>> subjects >>>> >> for each of the DataDomains to be configured. JavaGroups is >>>> peer-to-peer >>>> >> library that is embedded into applications. Default configuration >>>> provided >>>> >> by CayenneModeler will work out of the box, provided that IP multicast >>>> is >>>> >> enabled on the network." >>>> >> >>>> >> for the JMS solution the JMS server setup is a problem >>>> >> for the JavaGroups setup the "IP multicast is enabled on the network." >>>> is a >>>> >> problem >>>> >> >>>> >> so for the custom tranport mechanism that you mentioned I stumbled >>>> upon >>>> >> this here >>>> >> >>>> >> >>>> http://jee-bpel-soa.blogspot.com/2009/06/session-sharing-in-apache-tomcat.html >>>> >> >>>> >> which seems to describe cross context data sharing on tomcat web >>>> contexts >>>> >> >>>> >> but is there any code to look at to see how a custom transport >>>> mechanism can >>>> >> be setup? >>>> >> >>>> >> Tobias >>>> >> >>>> >> >>>> >> On Wed, Jul 29, 2009 at 8:28 PM, Mike Kienenberger <mkien...@gmail.com >>>> >wrote: >>>> >> >>>> >>> I've never set it up, but it's easily configurable. >>>> >>> >>>> >>> If you don't like the javagroups or JMS methodologies, you can define >>>> >>> your own -- I don't know what tomcat app-data-sharing ability is >>>> >>> available -- it probably depends on the container, but I don't >>>> >>> remember reading about any in the past. >>>> >>> >>>> >>> However, the docs seem to indicate that using Javagroups is pretty >>>> >>> painless with no external configuration to deal with. >>>> >>> >>>> >>> I have a Cayenne 1.1.x application I wrote that used remote >>>> >>> notification internally to broadcast events between sessions, so I >>>> >>> know it's not difficult to set up and define your own event >>>> >>> broadcaster. My guess is that doing it for javagroups is pretty easy >>>> >>> since it sounds like a matter of just filling in the forms on the >>>> >>> modeler. >>>> >>> >>>> >>> On Wed, Jul 29, 2009 at 2:15 PM, Tobias >>>> >>> Schoessler<tobias.schoess...@gmail.com> wrote: >>>> >>> > Thanks Mike, >>>> >>> > >>>> >>> > so the answer is yes, this can only be done using remote >>>> notification? is >>>> >>> > this correct? >>>> >>> > >>>> >>> > Isn't there a way to share the cache among two web application >>>> scopes >>>> >>> > without going through the hassle of setting up remote notification? >>>> >>> > >>>> >>> > When the two webapps are running on the same physical machine, >>>> inside the >>>> >>> > same application server this seems overkill. >>>> >>> > >>>> >>> > Tobias >>>> >>> > >>>> >>> > On Wed, Jul 29, 2009 at 6:50 PM, Mike Kienenberger < >>>> mkien...@gmail.com >>>> >>> >wrote: >>>> >>> > >>>> >>> >> Yes, >>>> >>> >> >>>> >>> >> Here's a Cayenne 2.0 document on it: >>>> >>> >> >>>> >>> >> http://cayenne.apache.org/doc20/configuring-caching-behavior.html >>>> >>> >> >>>> >>> >> For 3.0: >>>> >>> >> >>>> >>> >> http://cayenne.apache.org/doc/configuring-caching-behavior.html >>>> >>> >> >>>> >>> >> On Wed, Jul 29, 2009 at 12:46 PM, Tobias >>>> >>> >> Schoessler<tobias.schoess...@gmail.com> wrote: >>>> >>> >> > Hi, >>>> >>> >> > >>>> >>> >> > is it possible to sync the cayenne cache of two web applications >>>> >>> running >>>> >>> >> in >>>> >>> >> > the same tomcat? >>>> >>> >> > >>>> >>> >> > I observe one web app showing outdated data when the other is >>>> >>> committing >>>> >>> >> > updates. Both apps are using the same mapping configuration. >>>> >>> >> > >>>> >>> >> > Do I need to use remote notification for this? >>>> >>> >> > >>>> >>> >> > thanks >>>> >>> >> > >>>> >>> >> > Tobias >>>> >>> >> > >>>> >>> >> >>>> >>> > >>>> >>> >>>> >> >>>> > >>>> >>> >>> >> >
