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From Charles Proefrock <chas....@hotmail.com>
Subject RE: CPE to AS Transition ... Porting processingUnitThreadCount
Date Mon, 27 Oct 2008 01:34:28 GMT
We've made progress on our transition and now have an app and a configuration that we believe
should meet our needs.  We have an application derived from the RunRemoteAsyncAE with the
CR and 1 deployed Aggregate.  The deployed aggregate uses a mixture of numInstances and remoteAsyncEngines
to achieve the objectives outlined in my original message.  Not too much different than originally
described, but a better understanding of the AS approach to scale-up, surpassing what we had
achieved with the processingUnitThreadCount in the CPE application.
 
We are experiencing one problem at this point which I didn't expect.  Null CAS returned on
error conditions.
 
In our CPE implementation we manage a database queue by accessing the queue with a Collection
Reader and then completing the queue update via the StatusCallbackListener::entityProcessComplete()
call.  Independent of whether the call ends with success or error, the CAS reference is valid,
so we can access specific information about the CAS and properly update the database status.
 
Our first attempt at error detection in our AS implementation results in a null CAS passed
into the entityProcessComplete() call.  This occurs on a remote delegate timeout exception.
 I did not test other error scenarios to determine if the CAS is valid.
 
Please let me know how to configure the system to return a valid CAS reference on error to
the StatusCallbackListener.
 
Thanks,
 
Charles



> Date: Thu, 25 Sep 2008 09:27:18 -0400> From: eaepstein@gmail.com> To: uima-user@incubator.apache.org>
Subject: Re: CPE to AS Transition ... Porting processingUnitThreadCount> > In order
to optimize deployment, it is good to focus on where the work is> being done and then what
overhead is added by the framework.> > In your case all the work for components CR,
A, C and D is expected to be> done on Machine 0. Separating the CR from the aggregate adds
unnecessary CAS> serialization overhead for every document, so it would be better to move
the> CR into the aggregate. Components A, C or D can be replicated as needed> (using
numInstances as appropriate for each) in the one aggregate instance.> > Machines 1..N
are then used to scaleout multiple instances of B.> > RunRemoteAsyncAE could just send
an "empty" CAS to kick off the CR in the> aggregate, or the CAS could contain information
about the collection to be> processed by the CR.> > Note that RunRemoteAsyncAE is
a fairly simple application, and it is the> UIMA AS async API that optionally deploys colocated
services and/or> optionally instantiates a CR. My point is that RunRemoteAsyncAE could
be> replaced with a custom application that (via unspecified mechanisms) deploys> B
on remote machines, then deploys the aggregate in the same JVM, runs it,> and shuts everything
down at the end.> > Eddie> > On Thu, Sep 25, 2008 at 6:54 AM, Charles Proefrock
<chas.pro@hotmail.com>wrote:> > > I've reviewed Fig. 4 and Fig. 3. Our system
seems closer to Fig. 3> > (asingle Collection Reader (CR) with CasPool size X used to
push documents> > to X services).Assuming the "Service Instance" is an aggregate (AG)
with> > multiple AEsteps A..D, we are extending Fig. 3 with another level of remote>
> AE forone of the steps: Machine0: Broker + RunRemoteAsyncAE + 2 AG Service> > InstancesMachine1:
RemoteStepB_AE InstanceMachine2: RemoteStepB_AE> > Instance The AG descriptor is configured
with A..D in-line, and the AG> > deploymentdescriptor has a remote 'B' override, possibly
with error> > handlingcontrols, etc. CR --- || --2-- A B ---> > || --2-- remote
'B' C> > D (consumer) If I'm following your guidance, we should not use> > numInstances
in the AGdeployment descriptor because we have decided to> > remote 'B'. Instead weneed
to deploy the 2 AG Service Instances via our own> > launch mechanism(as either multiple
-d flags on RunRemoteAsyncAE, or> > independently intheir own processes). Let me know
if I'm on track.> > - Charles> >> >
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