Assuming your output is going to HDFS, you want to look at DFSClient. Reducer uses FileSystem to write the output. You need to start looking at how DFSClient chunks the output and sends them across to the remote data-nodes.
Thanks +Vinod On Jan 6, 2014, at 11:07 AM, nagarjuna kanamarlapudi <nagarjuna.kanamarlap...@gmail.com> wrote: > I want to have a look at the code where of flush operations that happens > after the reduce phase. > > Reducer writes the output to OutputFormat which inturn pushes that to memory > and once it reaches 90% of chunk size it starts to flush the reducer output. > > I essentially want to look at the code of that flushing operation. > > > What is the class(es) I need to look into > > > On Mon, Jan 6, 2014 at 11:23 PM, Hardik Pandya <smarty.ju...@gmail.com> wrote: > Please do not tell me since last 2.5 years you have not used virtual Hadoop > environment to debug your Map Reduce application before deploying to > Production environment > > No one can stop you looking at the code , Hadoop and its ecosystem is > open-source > > > On Mon, Jan 6, 2014 at 9:35 AM, nagarjuna kanamarlapudi > <nagarjuna.kanamarlap...@gmail.com> wrote: > > > ---------- Forwarded message ---------- > From: nagarjuna kanamarlapudi <nagarjuna.kanamarlap...@gmail.com> > Date: Mon, Jan 6, 2014 at 6:39 PM > Subject: Understanding MapReduce source code : Flush operations > To: mapreduce-u...@hadoop.apache.org > > > Hi, > > I am using hadoop/ map reduce for aout 2.5 years. I want to understand the > internals of the hadoop source code. > > Let me put my requirement very clear. > > I want to have a look at the code where of flush operations that happens > after the reduce phase. > > Reducer writes the output to OutputFormat which inturn pushes that to memory > and once it reaches 90% of chunk size it starts to flush the reducer output. > > I essentially want to look at the code of that flushing operation. > > > > > Regards, > Nagarjuna K > > > -- CONFIDENTIALITY NOTICE NOTICE: This message is intended for the use of the individual or entity to which it is addressed and may contain information that is confidential, privileged and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient, you are hereby notified that any printing, copying, dissemination, distribution, disclosure or forwarding of this communication is strictly prohibited. If you have received this communication in error, please contact the sender immediately and delete it from your system. Thank You.
