yes that's what I observe too. The messages sent when these updates occure,
do they contain the change infromation or only the information which objects
to invalidate? I got this asked when I asked for the multicast address, to
estiamte traffic for this setup.
On Thu, Jul 30, 2009 at 11:33 PM, Michael Gentry <mgentr..asslight.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.schoessle..mail.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.schoessle..mail.com> wrote:
> >
> >> Thanks everyone for the posts.
> >>
> >>..ike, 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?
> >>
> >>..alcolm, 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.edga..mail.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<mkienen..mail.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.schoessle..mail.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 <
> mkienen..mail.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.schoessle..mail.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 <
> >>> mkienen..mail.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.schoessle..mail.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
> >>> >>> >> >
> >>> >>> >>
> >>> >>> >
> >>> >>>
> >>> >>
> >>> >
> >>>
> >>
> >>
> >
>
This archive was generated by hypermail 2.0.0 : Thu Jul 30 2009 - 17:38:08 EDT