hadoop-common-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Harsh J <ha...@cloudera.com>
Subject Re: Why LineRecordWriter.write(..) is synchronized
Date Thu, 08 Aug 2013 10:50:42 GMT
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" <azuryyyu@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.bp@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 <azuryyyu@gmail.com> wrote:
>>
>>> because we may use multi-threads to write a single file.
>>> On Aug 8, 2013 2:54 PM, "Sathwik B P" <sathwik@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
>>>>
>>>
>>

Mime
View raw message