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From Manohar CS <Manohar...@itcinfotech.com>
Subject RE: Notification support from flume?
Date Mon, 08 Dec 2014 06:43:11 GMT
Hi Aravind,

You mentioned “You may be better off using something like an Oozie action to trigger a job
when the dataset is complete. ”  - But how will I know that flume completed its transfer
(moreover we want this to happen at regular intervals)

Thanks,
Manohar

From: Arvind Prabhakar [mailto:arvind@streamsets.com]
Sent: Monday, December 8, 2014 11:42 AM
To: user@flume.apache.org
Subject: Re: Notification support from flume?

Flume is not suited for file transfers as such. With that, please see my comments below:

- support for variable transaction size that could be set by the source or interceptor

The transactions are already variable sized. The only configuration that applies on top is
the maximum size of a transaction. How is this different from what you are proposing?


 - SpoolDir to support creation of one transaction per file

If the file is large, you would run out of heap space quickly. Also, how do you recover from
intermittent failures?

 - File and Memory channels to support spawning a process on transaction successful commit.
Such process can be a bash script, but that would be implemented in plug-able class

You may be better off using something like an Oozie action to trigger a job when the dataset
is complete.

Regards,
Arvind







On Sun, Dec 7, 2014 at 12:55 PM, Ahmed Vila <avila@devlogic.eu<mailto:avila@devlogic.eu>>
wrote:
Hi group,

Manohar's requirements sound valid. Guess there are other cases such "completion notification"
could come in handy.

Thus, I would propose these distinct features that would make this possible via configuration:
 - support for variable transaction size that could be set by the source or interceptor
 - SpoolDir to support creation of one transaction per file
 - File and Memory channels to support spawning a process on transaction successful commit.
Such process can be a bash script, but that would be implemented in plug-able class

The one thing I'm not sure about until I look at the code, if HDFSSink will write flush cache
to the HDFS once it encounters no more events in a transaction.

What do you guys think ?


On Sat, Dec 6, 2014 at 7:31 AM, Manohar CS <Manohar.CS@itcinfotech.com<mailto:Manohar.CS@itcinfotech.com>>
wrote:

Thanks Hari for your response.



My requirement goes like this -



1) There are bunch of files coming in at regular intervals (hourly or daily) in my spoolDir

2) I wan tthem to be moved into HDFS via HDFS sink using reg-ex like /target/%Y-%M%D so each
day file gets into different destination HDFS

3) Now once this flume completes copying files , I want to kick off my MR job.



Thanks,

Manohar

________________________________
From: Hari Shreedharan <hshreedharan@cloudera.com<mailto:hshreedharan@cloudera.com>>
Sent: Saturday, December 6, 2014 7:16 AM
To: user@flume.apache.org<mailto:user@flume.apache.org>
Cc: user@flume.apache.org<mailto:user@flume.apache.org>
Subject: Re: Notification support from flume?

Looking at .COMPLETED is not an indication that the data has been written out to HDFS. As
of now, unfortunately there is no way to tag an event as coming from a specific file. I can’t
think of a way to do this in a fool-proof way off the top of my mind. What is your use-case,
there might be another way to do the same thing?

Thanks,
Hari


On Fri, Dec 5, 2014 at 4:19 AM, Manohar CS <Manohar.CS@itcinfotech.com<mailto:Manohar.CS@itcinfotech.com>>
wrote:
Hi All,


I wanted to know if there is a way of notification mechanism or some way of finding out if
flume has finished transfer of certain file from spoolDir to HDFS sink? We know by looking
at .COMPLETED files in spoolDir we can assume its completed but wanted to know if there is
more reliable way of call back mechanism ?




Thanks,
Manohar.


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 third  party  in  any manner whatsoever without the specific consent  of  ITC  Infotech India
Ltd./ its Holding company/ its Subsidiaries/ its Group Companies.




Please consider the environment before printing this e-mail

Disclaimer: This  communication  is  for the exclusive use of the intended recipient(s) and
 shall  not attach any liability on the originator or ITC Infotech India Ltd./its  Holding
company/ its Subsidiaries/ its Group Companies. If you are the addressee, the contents of
this e-mail are intended for your use only and it shall  not be forwarded to any third party,
without first obtaining written authorization from the originator or ITC Infotech India Ltd./
its Holding company/its  Subsidiaries/ its Group Companies. It may contain information which
is confidential and legally privileged and the same shall not be used or dealt with  by any
 third  party  in  any manner whatsoever without the specific consent  of  ITC  Infotech India
Ltd./ its Holding company/ its Subsidiaries/ its Group Companies.




--

Best regards,
Ahmed Vila | Senior software developer
DevLogic | Sarajevo | Bosnia and Herzegovina

Office : +387 33 942 123<tel:%2B387%2033%20942%20123>
Mobile: +387 62 139 348<tel:%2B387%2062%20139%20348>

Website: www.devlogic.eu<http://www.devlogic.eu>
E-mail   : avila@devlogic.eu<mailto:avila@devlogic.eu>
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