Re: Manage a ROOT file from a streaming of the ROOT file content

Hi Hassen,

  the HDFS plugin is readonly. The idea is that you first copy the ROOT file onto HDFS and then access if with ROOT.

Cheers, Fons.

On 18/04/2012 09:44, Hassen Riahi wrote:
> Hi,
>
>> Hi,
>>
>> Another alternative is to try using the HDFS i/o plugin.
>
> Is there HDFS i/o plugin in ROOT? with which it is possible to write
> directly (not through Fuse) from ROOT to HDFS.
> If it is the case please point us to the documentation.
>
> cheers
> Hassen
>
>>
>> Cheers,
>> Philippe.
>>
>> On 4/17/12 10:29 AM, Massimiliano Fasi wrote:
>>> Hi all,
>>>
>>> In order to use Apache Hadoop with MapReduce streaming, we need a c++
>>> way to copy or cast a ROOT file passed through the standard input to any
>>> type of ROOT object (a TFile hopefully).
>>>
>>> Practically, we want to execute a command like
>>>
>>>> cat Myfile.root | MyAnalysisCode
>>>
>>> or
>>>
>>>> MyAnalysisCode < Myfile.root
>>>
>>> and then cast in MyAnalysisCode the standard input to something
>>> manageable by ROOT.
>>>
>>> Solutions we have tried so far didn't work. In particular, we tried to
>>> use the ifstream library but we wasn't able to cast their objects to
>>> something manageable by ROOT.
>>>
>>> Any hints or suggestions would be very appreciated.
>>>
>>> Thanks,
>>>
>>> Massimiliano
>>>
>>> ----------------------------------------------------------------
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>>>
>>>
>

-- 
Org:    CERN, European Laboratory for Particle Physics.
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