Thanks. So, to scan the table just using the java program without using MapReduce will heavily decrease the performance.
Yong On Tue, Aug 20, 2013 at 6:02 PM, Jeff Kolesky <j...@opower.com> wrote: > The scan will be broken up into multiple map tasks, each of which will run > over a single split of the table (look at TableInputFormat to see how it is > done). The map tasks will run in parallel. > > Jeff > > > On Tue, Aug 20, 2013 at 8:45 AM, yonghu <yongyong...@gmail.com> wrote: > > > Hello, > > > > I know if I use default scan api, HBase scans table in a serial manner, > as > > it needs to guarantee the order of the returned tuples. My question is > if I > > use MapReduce to read the HBase table, and directly output the results in > > HDFS, not returned back to client. The HBase scan is still in a serial > > manner or in this situation it can run a parallel scan. > > > > Thanks! > > > > Yong > > > > > > -- > *Jeff Kolesky* > Chief Software Architect > *Opower* >
