Grandl Robert 2013-07-22, 03:41
-Re: non-local map task input
Grandl Robert 2013-07-22, 17:06
Can anyone help me with this please ?
From: Grandl Robert <[EMAIL PROTECTED]>
To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
Sent: Sunday, July 21, 2013 8:41 PM
Subject: non-local map task input
I am trying to figure out all the points in hdfs code where hdfs traffic is read/written. As far as I can tell, it seems most of the traffic goes through BlockSender/BlockReceiver, right ?
However, when a client do a copyFromLocal, or read a file, or for a map task whose input is not local, it seems the DFSClient is invoked. I understand that with DFSClient, it gets the dananodes locations from namenode and then directly open a socket and read/writes. Anyway, I am not very sure where that happens. Can someone point me out where in the code I can find the exact calls to read/write from other datanodes with DFSClient ?
Thanks in advance,
Colin Patrick McCabe 2013-07-25, 23:46