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3 Replies Latest reply: Jan 9, 2013 2:10 AM by Junger He RSS

Is event timestamp globally unique in a cep application?

887796 Newbie
Currently Being Moderated
Hi,

We have an HA application with several HA input adapters. Each adapter is receiving a seperate stream of events (from seperate JMS adapters). One JMS adapter per HA adapter.

Is it possible that 2 events, coming gfrom 2 seperate ha adapters will have the same timestamp?

Thanks
  • 1. Re: Is event timestamp globally unique in a cep application?
    Junger He Explorer
    Currently Being Moderated
    Logically, the timestamp is different among different HA adapters.
  • 2. Re: Is event timestamp globally unique in a cep application?
    887796 Newbie
    Currently Being Moderated
    Hi,

    I am not sure I understand the answer.

    Is it possible that 2 events, one going thru HA inbound adapter 1 and the second going thru HA inbound adapter 2 will have the same timestamp?
  • 3. Re: Is event timestamp globally unique in a cep application?
    Junger He Explorer
    Currently Being Moderated
    Hi,

    Sorry for late reply. In an application, the same event passing through the same HA input adapter has the same timestamp even in different machines(servers).

    Let's consider the EPN as

    inputAdapter -> haInputAdapter1 -> channel1 -> processsor,
    -> haInputAdapter2 -> channel2 -> processor

    1) it's impossible to just let event 1 go thru haInputAdapter1 and event 2 thru haInputAdapter2
    2) If we add a inputAdapter 2 and configure haInputAdapter2 be its listener, the event's timestamp are different inherently. It's just a coincide to be same.
    3) Now we don't change the EPN, even event 1 received by inputAdapter and event 1 received by inputAdapter2 are on the same time, HA input adapter need to update the timestamp of the event, the timestamp through the ha input adapters are not guaranteed to be same because there is no such synchronization mechanism(this is not needed).

    Make sense?

    Junger

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