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Posted to jcs-users@jakarta.apache.org by Yaswanth <ya...@gmail.com> on 2009/03/19 10:16:50 UTC
Does Remote Client gets acknowledgment from the Remote Cache for
puts?
Hi ,
I have implemented Remote Cache with two clients and one Server.
First Clients puts an Object into the Cache and sends the key over JMS to
the second Client. Using which Second Client gets that Object from the
Remote Cache .
This entire thing is working for me on low loads .. When i load the system.
I observed that Second Client retrieves few null messages from the remote
cache..
My guess is that it would be only possible if the Second Client is trying to
retrieve the Object even before the First Client puts into remote Cache.
Is there anything(something like acknowledgments) with which i can ensure in
the Fist Client that i send the JMS Message only after my object is kept in
the remote cache.
Does a Remote Cache send back the acknowledgment to the clients when the
Object is put into the cache ?
These are my Cache Config Files ..
http://www.nabble.com/file/p22595967/remote.cache.server.ccf
remote.cache.server.ccf
http://www.nabble.com/file/p22595967/remote.cache.client.ccf
remote.cache.client.ccf
Thanks
Yaswanth
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Re: Does Remote Client gets acknowledgment from the Remote Cache
for puts?
Posted by Yaswanth <ya...@gmail.com>.
Hi,
Thanks for the reply ..
But that database option is not feasible for me .
K .. now lets think the other way .. Is it possible for the second client to
get notified when the first client puts a new Object into remote cache.. ?
Some listener kind of thing for call back ?
Thanks,
Yaswanth
Niall Gallagher wrote:
>
> Hi Yaswanth,
>
> Cache "puts" are asynchronous i.e. JCS sends data to the remote server
> in a background thread. This will almost definitely cause the behaviour
> (race condition) you're seeing.
>
> Re: acknowledgements: someone else might answer that I'm not sure. My
> hunch is that perhaps your use case isn't appropriate for a distributed
> cache which does asynchronous puts. As a workaround your sender could
> write your data to a database which is synchronous and also put it into
> the cache. The receiver could then fetch it from the cache if available
> or from the database if not. Though this use case could mean that you'll
> have a low cache hit rate on this data due to the race condition you're
> seeing.
>
> Niall
>
> On Thu, 2009-03-19 at 02:16 -0700, Yaswanth wrote:
>
>> Hi ,
>>
>> I have implemented Remote Cache with two clients and one Server.
>>
>> First Clients puts an Object into the Cache and sends the key over JMS to
>> the second Client. Using which Second Client gets that Object from the
>> Remote Cache .
>>
>> This entire thing is working for me on low loads .. When i load the
>> system.
>> I observed that Second Client retrieves few null messages from the remote
>> cache..
>>
>> My guess is that it would be only possible if the Second Client is trying
>> to
>> retrieve the Object even before the First Client puts into remote Cache.
>>
>> Is there anything(something like acknowledgments) with which i can ensure
>> in
>> the Fist Client that i send the JMS Message only after my object is kept
>> in
>> the remote cache.
>>
>> Does a Remote Cache send back the acknowledgment to the clients when the
>> Object is put into the cache ?
>>
>> These are my Cache Config Files ..
>> http://www.nabble.com/file/p22595967/remote.cache.server.ccf
>> remote.cache.server.ccf
>> http://www.nabble.com/file/p22595967/remote.cache.client.ccf
>> remote.cache.client.ccf
>>
>>
>> Thanks
>> Yaswanth
>
>
>
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Re: Does Remote Client gets acknowledgment from the Remote Cache
for puts?
Posted by Niall Gallagher <ni...@switchfire.com>.
Hi Yaswanth,
Cache "puts" are asynchronous i.e. JCS sends data to the remote server
in a background thread. This will almost definitely cause the behaviour
(race condition) you're seeing.
Re: acknowledgements: someone else might answer that I'm not sure. My
hunch is that perhaps your use case isn't appropriate for a distributed
cache which does asynchronous puts. As a workaround your sender could
write your data to a database which is synchronous and also put it into
the cache. The receiver could then fetch it from the cache if available
or from the database if not. Though this use case could mean that you'll
have a low cache hit rate on this data due to the race condition you're
seeing.
Niall
On Thu, 2009-03-19 at 02:16 -0700, Yaswanth wrote:
> Hi ,
>
> I have implemented Remote Cache with two clients and one Server.
>
> First Clients puts an Object into the Cache and sends the key over JMS to
> the second Client. Using which Second Client gets that Object from the
> Remote Cache .
>
> This entire thing is working for me on low loads .. When i load the system.
> I observed that Second Client retrieves few null messages from the remote
> cache..
>
> My guess is that it would be only possible if the Second Client is trying to
> retrieve the Object even before the First Client puts into remote Cache.
>
> Is there anything(something like acknowledgments) with which i can ensure in
> the Fist Client that i send the JMS Message only after my object is kept in
> the remote cache.
>
> Does a Remote Cache send back the acknowledgment to the clients when the
> Object is put into the cache ?
>
> These are my Cache Config Files ..
> http://www.nabble.com/file/p22595967/remote.cache.server.ccf
> remote.cache.server.ccf
> http://www.nabble.com/file/p22595967/remote.cache.client.ccf
> remote.cache.client.ccf
>
>
> Thanks
> Yaswanth