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From Aaron Smuts <asm...@yahoo.com>
Subject Re: Fwd: Query regarding remote cache
Date Thu, 12 May 2005 00:19:34 GMT
I'm not exactly sure what the question is either, but
maybe this will help.

There is no synchronization on startup in JCS.  It
doesn't exist.  I'm trying to figure out a way to do
it  . . .

JCS lets you can into regions, or what we sometimes
call a cache.  Think of a region as a hashtable that
you get out of JCS by name.

For each region you can configure plugins, or
auxiliaries, sort of like log4j appenders.

This is done on a region by region basis.  If machines
A and B have a region called foo and they are both
configured to have a distibution plugin, then they
will talk.  If machine B also has a region named bar,
but it is not configured for distribution, then
elements put in bar will not be distributed.

You could configure machine B to distribute bar to C
but not with A.

You can use jgroups, sockets, or the rmi centralized
server for distribution.  We will have a JMS option
soon.

(Outside of the http lateral plugins, currently there
is no really good way to just listen without also
sending.  There is also no good way to send without
listening.  That's why the JMS plugin would be useful.
  
We do have an http sender and a servlet listener that
will do the trick.  When we had embedded jetty this
worked well.  The JCSAdmin.jsp can also be used for
deletions, but there is no prebuilt jcs way to call
it.)

What we call the "remote cache" is the rmi server.  It
is robust, and has some failover capabilities.

Aaron





--- Hanson Char <hanson.char@gmail.com> wrote:

> ---------- Forwarded message ----------
> From: Hanson Char <hanson.char@gmail.com>
> Date: May 11, 2005 9:28 PM
> Subject: Re: Query regarding remote cache
> To: Hariprasath Manivannan
> <hari.manivannan@gmail.com>
> 
> 
> The given URL is referring to the use of "remote
> cache" in JCS, which
> is not applicable to the use of lateral cache.
> 
> Lateral cache is rather a "distributed index", which
> AFAIK tries to
> partition the entire cache into different nodes, but
> with no guarantee
> that the replicates of the same cache item is
> consistent among all
> nodes.
> 
> So is the original concern related to Remote or
> Lateral ?
> 
> Hanson
> 
> On 5/11/05, Hariprasath Manivannan
> <hari.manivannan@gmail.com> wrote:
> > Hi Hanson,
> >
> > I am looking into the following configuration for
> my needs:
> >
> > http://jakarta.apache.org/jcs/RemoteAuxCache.html
> >
> > Also my understanding about Remote Cache vs
> Lateral cache is:
> > The remote cache can get updates from the local
> cache only.
> > Lateral cache is also a kind of remote cache, but
> it can send update to the
> > local cache.
> >
> >
> >
> > Regards,
> > Hari
> >
> >
> > On 5/11/05, Hanson Char <hanson.char@gmail.com>
> wrote:
> > > Hari,
> > >
> > > I am starting to think we are talking about
> different things here.  We
> > > should clarify the terminology.
> > >
> > > 1) Are you referring to the use of a) remote
> cache server or b)
> > > lateral cache in JCS ?
> > > 2) What does it mean by "Remote Cache
> Synchronization" ?  Is it an
> > > extra step involved in the use of lateral cache
> ?  For AFAIK, there is
> > > no such thing in using the remote cache server.
> > >
> > > H
> > >
> > > On 5/11/05, Hariprasath Manivannan
> <hari.manivannan@gmail.com> wrote:
> > > > Hi Hanson,
> > > >
> > > > I have attached a word doc depicting the
> problem.
> > > >
> > > >
> > > >
> > > > Regards,
> > > > Hari
> > > >
> > > >
> > > > On 5/11/05, Hanson Char <hanson.char@gmail.com
> > wrote:
> > > > > What do you mean by "synchronization" ?  Do
> you mean when B tries to
> > > > > update it's local cache, or C tries to
> update it's local cache, or
> > > > > both ?  In all cases, A at most will only be
> affected by a bunch of
> > > > > cache item delete requests.
> > > > >
> > > > > Hanson
> > > > >
> > > > > On 5/11/05, Hariprasath Manivannan
> <hari.manivannan@gmail.com > wrote:
> > > > > > Hi Hanson,
> > > > > >
> > > > > > Thanks for reply.
> > > > > >
> > > > > > To clarify things about my query : The
> client A is again another
> > J2EE
> > > > > > application. I referred to client because
> it uses the data from my
> > > > datastore
> > > > > > application B.
> > > > > >
> > > > > > The scenario that I am worried is: If a
> new client application C
> > wants
> > > > to
> > > > > > use data from my store(using cache), then
> a cache will be setup at
> > > > client C
> > > > > > and at the contents will also be stored in
> the cache at "B"(My data
> > > > store
> > > > > > application). When synchronization
> happens, the cache at A will
> > updated
> > > > to
> > > > > > have the stuff that "C" requested.
> > > > > >
> > > > > > Regards,
> > > > > > Hari
> > > > > >
> > > > > >
> > > > > > On 5/11/05, Hanson Char <
> hanson.char@gmail.com> wrote:
> > > > > > > When you say "client" side A and
> "server" side B, do you mean A is
> > a
> > > > > > > client of server B, both using JCS (in
> remote cache mode) ?
> > > > > > >
> > > > > > > If so, when B synchronizes with the
> remote cache, the
> > corresponding
> > > > > > > cache items are flushed from A, so the
> client will never hold data
> > not
> > > > > > > relevant to it.
> > > > > > >
> > > > > > > Hanson Char
> > > > > > >
> > > > > > > On 5/11/05, Hariprasath Manivannan <
> hari.manivannan@gmail.com>
> > wrote:
> > > > > > > > Hi,
> > > > > > > >
> > > > > > > > I am planning to use the remote cache
> feature of JCS in my J2EE
> > > > based
> > > > > > > > application. Basically my core
> application is a static
> > data-store.
> > > > Since
> > > > > > the
> > > > > > > > data is static, I decided to use the
> remote cache feature as
> > this
> > > > can
> > > > > > reduce
> > > > > > > > the RMI calls and network traffic.
> > > > > > > >
> > > > > > > > Now if I have a cache and both server
> side and client side, then
> > I
> > > > may
> > > > > > face
> > > > > > > > issue during the remote caches
> synchronization. The server side
> > > > cache
> > > > > > will
> > > > > > > > be a global cache containing all the
> cached objects. This is
> > fine.
> > > > But
> > > > > > once
> > > > > > > > synchronization is complete, the
> client cache's will become
> > similar
> > > > in
> > > > > > > > content to the server side cache. So
> for any given client
> > > > application
> > > > > > cache
> > > > > > > > will be holding data which is not
> relevant to that application.
> > > > > > > >
> > > > > > > > Is there any way where by I still
> maintain the remote cache, but
> > > > > > synchronize
> > > > > > > > with primary cache server
> "selectively" - based on a application
> > ID
> > > > or
> > > > > > > > something like that.
> > > > > > > >
> > > > > > > > Regards,
> > > > > > > > Hari
> > > > > > > >
> 
=== message truncated ===


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