hadoop-hdfs-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Sidharth Kumar <sidharthkumar2...@gmail.com>
Subject Anatomy of read in hdfs
Date Thu, 06 Apr 2017 19:55:52 GMT
Hi Genies,

I have a small doubt that hdfs read operation is parallel or sequential
process. Because from my understanding it should be parallel but if I read
"hadoop definitive guide 4" in anatomy of read it says "*Data is streamed
from the datanode back **to the client, which calls read() repeatedly on
the stream (step 4). When the end of the **block is reached, DFSInputStream
will close the connection to the datanode, then find **the best datanode
for the next block (step 5). This happens transparently to the client, **which
from its point of view is just reading a continuous stream*."

So can you kindly explain me how read operation will exactly happens.

Thanks for your help in advance


View raw message