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Re: [milo-dev] Milo Client-OpcUaSubscription class
In that sense yes...Thanks kevin.

On Mon, Dec 11, 2017 at 6:04 PM, Kevin Herron <kevinherron@xxxxxxxxx> wrote:
Sequential delivery of notifications is the only way to ensure your client has the latest and correct value for the things your'e subscribed to. If you process out of order the last value you "see" may not be the current value.

On Mon, Dec 11, 2017 at 1:12 AM, Isuru Samaraweera <isuru@xxxxxxxx> wrote:
Yes right..Also I have noted 2 queues are used deliveryQueue and ProcessingQue to achieve serial execution one by one in OpcUaSubscriptionManager.
Is it a specification requirement to process them sequentially?I do not see any message loss or inconsistencies even if queues are not used.

Messages  will be processed adhoc manner if these 2 queues are not used.

i e replace 
processingQueue.submit(() -> onPublishComplete(response));

with
executorService.submit(() -> onPublishComplete(response))


Please clarify.

Thanks
Isuru

On Sun, Dec 10, 2017 at 8:48 PM, Kevin Herron <kevinherron@xxxxxxxxx> wrote:
No, this semaphore is used internally to ensure that notification delivery and item creation are mutually exclusive in order to ensure that the item creation callback runs at a time that notifications aren't being processed.

A semaphore with only 1 permit can also be thought of as a Mutex.

On Sun, Dec 10, 2017 at 6:58 AM, Isuru Samaraweera <isuru@xxxxxxxx> wrote:
Hi All,
There is a semaphore defined as below in the OpcUaSubscription class.
 private final AsyncSemaphore notificationSemaphore = new AsyncSemaphore(1);

Shouldn't the number of permits depend on the OPC servers capacity to process ?
Should't it be configurable per client/server environment pair?

Thanks,
Isuru

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