Then is this a bug?  Synchronization in absence of any race condition is 
normally considered "bad".

In any case id like to know why this writer is synchronized whereas the other 
one are not.. That is, I think, then point at issue: either other writers 
should be synchronized or else this one shouldn't be - consistency across the 
write implementations is probably desirable so that changes to output formats 
or record writers don't lead to bugs in multithreaded environments .

On Aug 8, 2013, at 6:50 AM, Harsh J <ha...@cloudera.com> wrote:

> While we don't fork by default, we do provide a MultithreadedMapper 
> implementation that would require such synchronization. But if you are asking 
> is it necessary, then perhaps the answer is no.
> 
> On Aug 8, 2013 3:43 PM, "Azuryy Yu" <azury...@gmail.com> wrote:
>> its not hadoop forked threads, we may create a line record writer, then call 
>> this writer concurrently.
>> 
>> On Aug 8, 2013 4:00 PM, "Sathwik B P" <sathwik...@gmail.com> wrote:
>>> Hi,
>>> Thanks for your reply.
>>> May I know where does hadoop fork multiple threads to use a single 
>>> RecordWriter.
>>> 
>>> regards,
>>> sathwik
>>> 
>>> On Thu, Aug 8, 2013 at 7:06 AM, Azuryy Yu <azury...@gmail.com> wrote:
>>>> because we may use multi-threads to write a single file.
>>>> 
>>>> On Aug 8, 2013 2:54 PM, "Sathwik B P" <sath...@apache.org> wrote:
>>>>> Hi,
>>>>> 
>>>>> LineRecordWriter.write(..) is synchronized. I did not find any other 
>>>>> RecordWriter implementations define the write as synchronized.
>>>>> Any specific reason for this.
>>>>> 
>>>>> regards,
>>>>> sathwik

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