Suho,
Thanks for the reply. What I am thinking is why we need a receiver queue,
if we made DAS1->DAS2 async?
On Wednesday, January 31, 2018, Sriskandarajah Suhothayan <s...@wso2.com>
wrote:
> AFAIR the event queue is used for buffering the events when states are
> being synced, else there will be back pressure on the clients.
> I think the rationale for using the same thread with synchronous call and
> performing operations in both DAS1 and DAS2 ( in the order DAS1 -> DAS2 ->
> DAS2-Siddhi -> DAS1-Siddhi) is to make sure both nodes have processed the
> same events at the same time.
>
> I think event processing can be made asynchronous, such that the DAS1's
> threads send the event to DAS2 and then returns (DAS1 -> DAS2 -> DAS1), and
> a separate thread pool can handle sending events into DAS2-Siddhi.
> One possible option is depicted in the image attached.
>
> WDYT?
>
> On Wed, Jan 31, 2018 at 1:15 PM, Nirmal Fernando <nir...@wso2.com> wrote:
>
>> Thanks, Grainier. Please see my comments inline.
>>
>> On Wed, Jan 31, 2018 at 1:07 PM, Grainier Perera <grain...@wso2.com>
>> wrote:
>>
>>> InputEventDispatcher will send the event to the callback immediately
>>> while QueueInputEventDispatcher will queue events first and there will be
>>> an internal worker (QueueInputEventDispatcherWorker) which send the
>>> events to the callback.
>>>
>> The reason to accumulate events in a queue in HA is to be used for event
>>> syncing. If the event duplicated in the cluster is set to false, then this
>>> queue will be used for the event sync among other nodes in the HA
>>> deployment.
>>>
>>
>> Actually it's the same QueueInputEventDispatcherWorker which will do the
>> event sync too, AFAIU. But why a queue? Is it because event sync is a
>> synchronous operation (DAS1 -> DAS2 -> DAS2-Siddhi -> DAS1)? If so, then my
>> next question is, why does the event sync has to be synchronous?
>>
>>
>>> Regards,
>>> Grainier
>>>
>>> On Wed, Jan 31, 2018 at 6:31 AM, Nirmal Fernando <nir...@wso2.com>
>>> wrote:
>>>
>>>> Hi All,
>>>>
>>>> Can any of you remember the reason for using a receiver queue in HA
>>>> mode?
>>>>
>>>> if (mode == Mode.HA) {
>>>> HAConfiguration haConfiguration =
>>>> EventReceiverServiceValueHolder.getEventManagementService()
>>>> .getManagementModeInfo().getHaConfiguration();
>>>> Lock readLock =
>>>> EventReceiverServiceValueHolder.getCarbonEventReceiverManagementService().getReadLock();
>>>> inputEventDispatcher = new QueueInputEventDispatcher(tenantId,
>>>> EventManagementUtil.constructEventSyncId(tenantId,
>>>> eventReceiverConfiguration.getEventReceiverName(),
>>>> Manager.ManagerType.Receiver),
>>>> readLock, exportedStreamDefinition,
>>>> haConfiguration.getEventSyncReceiverMaxQueueSizeInMb(),
>>>> haConfiguration.getEventSyncReceiverQueueSize());
>>>> inputEventDispatcher.setSendToOther(!isEventDuplicatedInCluster);
>>>> EventReceiverServiceValueHolder.getEventManagementService()
>>>> .registerEventSync((EventSync) inputEventDispatcher,
>>>> Manager.ManagerType.Receiver);
>>>> } else {
>>>> inputEventDispatcher = new InputEventDispatcher();
>>>> }
>>>>
>>>>
>>>> --
>>>>
>>>> Thanks & regards,
>>>> Nirmal
>>>>
>>>> Technical Lead, WSO2 Inc.
>>>> Mobile: +94715779733 <+94%2071%20577%209733>
>>>> Blog: http://nirmalfdo.blogspot.com/
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Grainier Perera
>>> Senior Software Engineer
>>> Mobile : +94716122384 <+94%2071%20612%202384>
>>> WSO2 Inc. | http://wso2.com
>>> lean.enterprise.middleware
>>>
>>
>>
>>
>> --
>>
>> Thanks & regards,
>> Nirmal
>>
>> Technical Lead, WSO2 Inc.
>> Mobile: +94715779733 <071%20577%209733>
>> Blog: http://nirmalfdo.blogspot.com/
>>
>>
>>
>
>
> --
>
> *S. Suhothayan*
> Director
> *WSO2 Inc. *
> http://wso2.com <http://wso2.com/>
>
>
> *cell: (+94) 779 756 757 | blog: http://suhothayan.blogspot.com/
> <http://suhothayan.blogspot.com/>twitter: http://twitter.com/suhothayan
> <http://twitter.com/suhothayan> | linked-in:
> http://lk.linkedin.com/in/suhothayan <http://lk.linkedin.com/in/suhothayan>*
>
--
Thanks & regards,
Nirmal
Technical Lead, WSO2 Inc.
Mobile: +94715779733
Blog: http://nirmalfdo.blogspot.com/
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