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From Gowtham S <seldomgowt...@gmail.com>
Subject Re: Problem in running a same PE in multiple nodes
Date Sat, 23 Feb 2013 18:55:45 GMT
hi matthieu,

i have no problem in app. and also 3 nodes are processing the whole data
while one has stopped after some time..

i have attached the sample project of our application. most of the
description regarding the application is given in the attachment. if
possible try checking it.. i ran it in a single machine with 4 nodes as
said in previous message.


i will describe what is actually happening ...

i am having a record in which there are 18237 lines in which each line has
4 numbers. i m just trying to sort four numbers in each line based on the
design of PE's as given in the document.

same result one node stopped printing in the terminal while the other three
continues it work.

see this after reading the document..

after seeing the document u will see the PE graph... in that Processing PE
with Key ID "1" and Processing PE with Key ID "10" are running in the same
node..

 ProcessingPE with Key Id "10" should receive events from ProcessingPE of
ID(0 and 1) but it mainly receives events from only PE with Key id "1" and
not from Key Id  "0".

so i cant get alternate events from both PE's. but i should receive events
from both PE's one after the other as i  should sort 4 numbers in a single
line. so PE in one node is not sending events that much quick to the PE in
other nodes than to the PE in same node..

so Processing PE with id "10" receives more events from PE with key ID "0"
which is in the same node. so what i have to do in order to get events from
both PE's with id "0" and "1" one after the other rather than majorly from
"1" and then finally from "1"(i.e for e.g if "10" should receive 100 from
both "0" and "1".. first 100 is received from "1" which is at the same node
as "10" at that time only 2 or 3 received from "0". then the remaining from
"0" is received. but i should receive 1 event from "0 " and 1 from "1" and
so on ).

"0" ,"1" - are Processing PE with Key ID "0" and "1".







On Fri, Feb 22, 2013 at 7:03 PM, Matthieu Morel <mmorel@apache.org> wrote:

> Thanks for the info,
>
> with the cluster status that you show - which look ok - is there any
> problem with the app?
>
> Also, I would again recommend to check whether all data is processed as
> expected, regardless of the location. Can you check that?
>
> Thanks,
>
> Matthieu
>
>
> On Feb 22, 2013, at 14:02 , Gowtham S wrote:
>
> sorry for the wrong thread and gimp format..
>
> here i have attached the .png format of the screenshot which shows that
> all the 4 nodes are active .
>
> and also i didnt modify the hash function. when ever i run it in 4 nodes,
> it always map the 4 different keyed PE to four different nodes. i didnt
> manually  change the hash function ..
>
>
>
> On Thu, Feb 21, 2013 at 1:30 AM, Matthieu Morel <mmorel@apache.org> wrote:
>
>> Hi Jihyoun,
>>
>> PE graphs with cycles can certainly get a bit tricky sometimes, but
>> mainly because they can lead to deadlocks.
>>
>> I don't see how you'd lose events in the case you present if you don't
>> lose or reconfigure nodes. In the very specific case of sending an event
>> from PE instance a1 to the same PE instance a1, the event is simply put in
>> an in-memory blocking queue.
>>
>> It would be great to understand in which conditions you can see this
>> issue. Could you be more specific? (I can't reproduce that with simple
>> tests, but I don't have your own settings/code/environment).
>>
>> Thanks,
>>
>> Matthieu
>>
>> On Feb 20, 2013, at 03:04 , JiHyoun Park wrote:
>>
>> Dear Matthieu
>>
>> I also experienced the same problem with Gowtham.
>> Unlike him, I created a downstream to itself with only one key. (It was
>> like a flag to be turned on/off.)
>> I tested it and found sometimes one PE instance does not receive the
>> event.
>> I remember that it didn't depend on a specific node.
>>
>> At the time, I also wondered why.
>> Since it's a very simple logic, you can test it by yourself without much
>> efforts.
>> It would be really appreciated if you can tell us the solution or at
>> least the reason.
>>
>> Best Regards
>> Jihyoun
>>
>>
>>
>> On Tue, Feb 19, 2013 at 11:38 PM, Matthieu Morel <mmorel@apache.org>wrote:
>>
>>> Hi,
>>>
>>> Can you provide more detail about a node not running correctly? what
>>> does that mean to you, that it does not receive messages? Maybe that's
>>> normal because of the distribution of keys. Or maybe you only have 3 active
>>> nodes in the cluster. (you can check that with the s4 status tool)
>>>
>>> The distribution of keys across nodes is a simple hash+mod , which you
>>> can override if needed.
>>>
>>> I would recommend to check whether all data is processed as expected,
>>> regardless of the location.
>>>
>>> Let us know,
>>>
>>> thanks,
>>>
>>> Matthieu
>>>
>>>
>>> On Feb 19, 2013, at 16:27 , Gowtham S wrote:
>>>
>>> Hi S4 community,
>>>
>>> I have been working with s4 piper for 3 months. now i am just trying to
>>> make a downstream from a PE to the same PE with different Key Id.
>>>
>>> i just have a scenario in which i would have an unique PE whose
>>> downstream is also to that PE  but each time the Key Id of the targeted PE
>>> may vary. this continues until it satisfies a condition where it just stops.
>>>
>>> i started implementing this in a single machine with 4 nodes, as i had 4
>>> different keys for that unique PE(say 0,1,2,3). so now every node will have
>>> that PE clone with one individual key Id from the available Key Ids. one PE
>>> may send some events to PE in other  nodes , until certain condition is
>>> reached where the process is stopped.
>>>
>>> now three nodes are running correctly except one node.. i wonder why ..
>>> because all the nodes have same computational part to execute.
>>>
>>> please help me as how s4 deals while assigning a single PE to different
>>> nodes with different key Id ..
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Tue, Feb 19, 2013 at 8:22 PM, Gowtham S <seldomgowtham@gmail.com>wrote:
>>>
>>>> Hi S4 community,
>>>>
>>>>
>>>
>>>
>>
>>
> <s4image.png>
>
>
>

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