It is a regular process, unless you explicitly say you want it to be java, which would be a bit odd to do, but possible.
--Bobby On 4/5/12 3:14 PM, "Mark question" <markq2...@gmail.com> wrote: Thanks for the response Robert .. so the overhead will be in read/write and communication. But is the new process spawned a JVM or a regular process? Thanks, Mark On Thu, Apr 5, 2012 at 12:49 PM, Robert Evans <ev...@yahoo-inc.com> wrote: > Both streaming and pipes do very similar things. They will fork/exec a > separate process that is running whatever you want it to run. The JVM that > is running hadoop then communicates with this process to send the data over > and get the processing results back. The difference between streaming and > pipes is that streaming uses stdin/stdout for this communication so > preexisting processing like grep, sed and awk can be used here. Pipes uses > a custom protocol with a C++ library to communicate. The C++ library is > tagged with SWIG compatible data so that it can be wrapped to have APIs in > other languages like python or perl. > > I am not sure what the performance difference is between the two, but in > my own work I have seen a significant performance penalty from using either > of them, because there is a somewhat large overhead of sending all of the > data out to a separate process just to read it back in again. > > --Bobby Evans > > > On 4/5/12 1:54 PM, "Mark question" <markq2...@gmail.com> wrote: > > Hi guys, > quick question: > Are there any performance gains from hadoop streaming or pipes over > Java? From what I've read, it's only to ease testing by using your favorite > language. So I guess it is eventually translated to bytecode then executed. > Is that true? > > Thank you, > Mark > >
