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From Dennis <>
Subject Re: DeltaManager for Clustering
Date Fri, 29 Jul 2005 21:19:21 GMT
Rainer Jung wrote:

>No, DeltaManager doesn't use that flag. It would somehow not make sense,
>because the whole pupose of DeltaManager is to only replicate changed
>attributes of a session and the flag tries to replicate every session
>accessed. So if you would impement it with DeltaManager it would behave
>the same way as the SimpleTcpReplicationManager already does.
Wouldn't there usually be only one session accessed per request?  At
least in my application, when a request is processed, I don't have any
code to access another user's sessions besides the one that made the
request.  So while this may be more overhead than only replicating a
session if something has changed, and again more overhead than only
replicating the changed attributes (DeltaManager), at least it solves my
problem of the 3rd party library that doesn't call setAttribute.

>Under high load that will be a problem. If that is relevant yu must do a
>stress test and observe CPU/bandwidth/latency.
I do agree that it would be important to watch bandwidth/latency to make
sure SimpleTcpReplicationManager can handle our load.

>Maybe a crude workaround: at the end of the requst do a
>getAttribute/setAttribute to the attributes you want to replicate. I think
>DeltaManager does not really check for a change, it replicates all
>attributes accessed via setAttribute.
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