Thank you guys for the valuable inputs. Regards, Mohammad Tariq
On Thu, Jun 28, 2012 at 10:27 AM, Lars George <[email protected]> wrote: > Yes exactly, this plus what Mohammad says, use the internal scanner to get > just the data from the region once you are in the coprocessor code. There is > an example of that in the book as well, here the online repo: > https://github.com/larsgeorge/hbase-book/blob/master/ch04/src/main/java/coprocessor/RowCountEndpoint.java > > Lars > > On Jun 28, 2012, at 7:36 AM, fding hbase wrote: > >> HTable api document shows: >> >> <T extends CoprocessorProtocol, R> Map<byte[],R> coprocessorExec( >> Class<T> protocol, byte[] startKey, byte[] endKey, Batch.Call<T,R> >> callable) >> throws IOException, Throwable; >> >> >> startKey && endKey bounds the region of your interest. >> >> On Thu, Jun 28, 2012 at 5:43 AM, Mohammad Tariq <[email protected]> wrote: >> >>> Aman, Lars, >>> >>> If I already know in advance that a particular region >>> holds the data of my interest, then how can I use Coprocessor to >>> operate on that region only and not on all the regions of a particular >>> table??Thank you. >>> >>> Regards, >>> Mohammad Tariq >>> >>> >>> On Wed, Jun 27, 2012 at 11:57 PM, Lars George <[email protected]> >>> wrote: >>>> Hi Mohammad, >>>> >>>> Not sure I follow. :( >>>> >>>> Coprocessor is not MapReduce. MapReduce already takes care to run your >>> code local to the data. >>>> >>>> Coprocessors can be seen like lightweight Map-only MapReduce job. >>>> >>>> You need to share a few more details for us to be able to help. >>>> >>>> Thanks, >>>> Lars >>>> >>>> On Jun 26, 2012, at 7:44 PM, Mohammad Tariq wrote: >>>> >>>>> Hello Lars, >>>>> >>>>> Thank you so much for the quick response.Actually, I want to >>>>> run my MapReduce jobs on a region that contains a specific set of >>>>> data. >>>>> >>>>> Regards, >>>>> Mohammad Tariq >>>>> >>>>> >>>>> On Tue, Jun 26, 2012 at 9:18 PM, Lars George <[email protected]> >>> wrote: >>>>>> Hi Mohammad, >>>>>> >>>>>> The code runs on the server which is opening the region. It sounds to >>> me that this is not what you want and that you need to have access to some >>> sort of resources only available on one specific server? Because if that is >>> not the case, then you are simply using the coprocessors the wrong way IMHO. >>>>>> >>>>>> Lars >>>>>> >>>>>> On Jun 26, 2012, at 6:44 PM, Mohammad Tariq wrote: >>>>>> >>>>>>> Hello list, >>>>>>> >>>>>>> Is it possible to use Coprocessors on some specific >>>>>>> regionservers instead of a per-region basis??As per my understanding a >>>>>>> coprocessor allows us to run the code directly on each region >>>>>>> server.Please correct me if I am wrong.Many thanks. >>>>>>> >>>>>>> Please correct me if I am wrong. >>>>>>> Regards, >>>>>>> Mohammad Tariq >>>>>> >>>> >>> >> >> >> >> -- >> >> Best Regards! >> >> Fei Ding >> [email protected] >
