OnAlarm on Pick activity stops working

[Fred van Engen]

Hi,

Maybe this is related to the problem posted by [hidden email]
who had a problem with OnAlarm on a scope.

We have a problem with OnAlarm in a Pick activity. The code looks like this:

<repeatUntil>
    <scope name="AlarmScope">
        <documentation>Needed because pick.onAlarm seems to trigger only
once in a loop</documentation>
        <sequence>
            <if name="IfPollTime">
                    <condition>...</condition>
                        <assign name="AssignShortPollTime">
                            <documentation>Poll often</documentation>
                                <copy>
                                    <from>'P0Y0M0DT0H1M0.0S'</from>
                                        <to variable="PollTime"/>
                                </copy>
                        </assign>
                        <elseif>
                            <condition>...</condition>
                                <assign name="AssignLongPollTime">
                                    <documentation>Poll less
often</documentation>
                                        <copy>
                                            <from>'P0Y0M0DT0H15M0.0S'</from>
                                                <to variable="PollTime"/>
                                        </copy>
                                </assign>
                        </elseif>
                        <else>
                            <assign name="AssignNoPollTime">
                                    <documentation>This duration should
be enough to never poll in practice even though polling would be
harmless</documentation>
                                        <copy>
                                            <from>'P1Y0M0DT0H0M0.0S'</from>
                                                <to variable="PollTime"/>
                                        </copy>
                                </assign>
                        </else>
                </if>
                <pick name="PickPoll">
                    <onMessage partnerLink="Partner" operation="Add"
portType="ns16:PortType" variable="AddPollIn">
                            <correlations>
                                    <correlation set="wzrd_set"
initiate="no"/>
                                </correlations>
                                <assign name="AssignAdd">
                                  ... add something to poll ...
                                </assign>
                        </onMessage>
                        <onMessage partnerLink="Partner"
operation="Remove" portType="ns16:PortType" variable="RemovePollIn">
                            <correlations>
                                    <correlation set="wzrd_set"
initiate="no"/>
                                </correlations>
                                <assign name="AssignRemove">
                                  ... remove something to poll ...
                                </assign>
                        </onMessage>
                        <onAlarm>
                            <for>$PollTime</for>
                                <sequence>
                                    <forEach name="ForEachPoll"
parallel="no" counterName="ForEachPollCounter">
                                           
<startCounterValue>1</startCounterValue>
                                               
<finalCounterValue>...</finalCounterValue>
                                                <scope name="PollScope">
                                                    <variables>
                                                       ...
                                                        </variables>
                                                        <faultHandlers>
                                                            <catchAll>
                                                                   
<empty name="LogFault">
                                                                       
</empty>
                                                                </catchAll>
                                                        </faultHandlers>
                                                       ... invoke
partner ...
                                                </scope>
                                        </forEach>
                                </sequence>
                        </onAlarm>
                </pick>
        </sequence>
    </scope>
    <condition>...</condition>
</repeatUntil>

Basically an external partner decides what to poll for at another
partner. The polling interval is variable, based on what is being
polled. Because changes by the client process must be possible at all
times, we use a Pick activity with some OnMessage handlers and an
OnAlarm handler.

The problem is that sometimes the OnAlarm handler won't be executed
anymore. After restarting BPELSE the OnAlarm handler will be called
again. Persistence is enabled.

I surrounded the Pick activity with a Scope because it seemed to help.
Unfortunately the problem reappeared during a test.

Any hints or work-arounds?


Regards,

Fred.


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[Fred van Engen]

Hi again,

Fred van Engen wrote:
> Hi,
>
> Maybe this is related to the problem posted by [hidden email]
> who had a problem with OnAlarm on a scope.
>
> We have a problem with OnAlarm in a Pick activity. The code looks like
> this:
>
...

> Basically an external partner decides what to poll for at another
> partner. The polling interval is variable, based on what is being
> polled. Because changes by the client process must be possible at all
> times, we use a Pick activity with some OnMessage handlers and an
> OnAlarm handler.
>
> The problem is that sometimes the OnAlarm handler won't be executed
> anymore. After restarting BPELSE the OnAlarm handler will be called
> again. Persistence is enabled.
>
> I surrounded the Pick activity with a Scope because it seemed to help.
> Unfortunately the problem reappeared during a test.
>

Monitoring is also enabled. It shows that the PollTime variable is set
correctly to the 1 or 15 minute interval and also shows that the pick
activity last longer than that without executing the OnAlarm activity.

When building I get a warning that the duration string has an incorrect
type in the assign to PollTime, but the assignment works (though the
OnAlarm stops working sometimes) and I can't think of a way to cast it
to an xsd:duration.
> Any hints or work-arounds?
>
Thanks for any help.


Fred.

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[Fred van Engen]

Hi again,

I noticed that the OnAlarm handler was executed if any unrelated message
was processed. I also had suspended instances in BPELSE at the time.

So I looked at the BPELSE sources to see what could cause this problem.

Could this be a bug in ReadyToRunQueue.getNextNonSuspendedBPIT ?

ReadyToRunQueue.getNextScheduledTime is used to determine how long to
wait before calling BPELProcessManagerImpl.process() again if no
messages are received from the NMR.

http://fisheye5.atlassian.com/browse/open-jbi-components/ojc-core/bpelse/bpelcore/src/com/sun/jbi/engine/bpel/core/bpel/engine/impl/ReadyToRunQueue.java?r=1.33#l273

If some instance with a timeout is suspended, it will likely end up
being the one that has expired earliest (mMostRecentlyExpiringBPIT) and
getNextScheduledTime will use getNextNonSuspendedBPIT to get a
non-suspended alternative. But getNextNonSuspendedBPIT  will only return
a BPIT that has expired already.

http://fisheye5.atlassian.com/browse/open-jbi-components/ojc-core/bpelse/bpelcore/src/com/sun/jbi/engine/bpel/core/bpel/engine/impl/ReadyToRunQueue.java?r=1.33#l280 


If no running instance is expired, getNextScheduledTime will return zero
and BPELSEInOutThread.run() will call DeliveryChannel.accept() without
timeout. So it will wait indefinitely until a message arrives.

http://fisheye5.atlassian.com/browse/open-jbi-components/ojc-core/bpelse/bpeljbiadapter/src/com/sun/jbi/engine/bpel/BPELSEInOutThread.java?r=1.41#l152

If getNextNonSuspendedBPIT would return the earliest BPIT to expire (as
its name suggests), BPELSE would end up calling DeliveryChannel.accept
with a timeout and OnAlarm would be executed as expected.

Correct?


Regards,

Fred.


Fred van Engen wrote:

> Hi again,
>
> Fred van Engen wrote:
>> Hi,
>>
>> Maybe this is related to the problem posted by [hidden email]
>> who had a problem with OnAlarm on a scope.
>>
>> We have a problem with OnAlarm in a Pick activity. The code looks
>> like this:
>>
> ...
>> Basically an external partner decides what to poll for at another
>> partner. The polling interval is variable, based on what is being
>> polled. Because changes by the client process must be possible at all
>> times, we use a Pick activity with some OnMessage handlers and an
>> OnAlarm handler.
>>
>> The problem is that sometimes the OnAlarm handler won't be executed
>> anymore. After restarting BPELSE the OnAlarm handler will be called
>> again. Persistence is enabled.
>>
>> I surrounded the Pick activity with a Scope because it seemed to
>> help. Unfortunately the problem reappeared during a test.
>>
> Monitoring is also enabled. It shows that the PollTime variable is set
> correctly to the 1 or 15 minute interval and also shows that the pick
> activity last longer than that without executing the OnAlarm activity.
>
> When building I get a warning that the duration string has an
> incorrect type in the assign to PollTime, but the assignment works
> (though the OnAlarm stops working sometimes) and I can't think of a
> way to cast it to an xsd:duration.
>> Any hints or work-arounds?
>>
> Thanks for any help.
>
> Fred.
>
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> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]
>

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