Sorry, one last question. On the map method, I have access to the row using the values parameter. Now, based on the value content, I might want to delete it. Do I have access to the table directly from one of the parameters? Or should I call the delete using an HTableInterface from my pool?
Thanks, JM 2012/11/2, Jean-Marc Spaggiari <[email protected]>: > Yep, you perfectly got my question. > > I just tried and it's working perfectly! > > Thanks a lot! I now have a lot to play with. > > JM > > 2012/11/2, Shrijeet Paliwal <[email protected]>: >> JM, >> >> I personally would chose to put it neither hadoop libs nor hbase libs. >> Have >> them go to your application's own install directory. >> >> Then you could sent the variable HADOOP_CLASSPATH to have your jar (also >> include hbase jars, hbase dependencies and dependencies your program >> needs) >> And to execute fire 'hadoop jar' command. >> >> An example[1]: >> >> Set classpath: >> export HADOOP_CLASSPATH=`hbase classpath`:mycool.jar:mycooldependency.jar >> >> Fire following to launch your job: >> hadoop jar mycool.jar hbase.experiments.MyCoolProgram >> -Dmapred.running.map.limit=50 >> -Dmapred.map.tasks.speculative.execution=false aCommandLineArg >> >> >> Did I get your question right? >> >> [1] In the example I gave `hbase classpath` gets you set with all hbase >> jars. >> >> >> >> On Fri, Nov 2, 2012 at 11:56 AM, Jean-Marc Spaggiari < >> [email protected]> wrote: >> >>> Hi Shrijeet, >>> >>> Helped a lot! Thanks! >>> >>> Now, the only think I need is to know where's the best place to put my >>> JAR on the server. Should I put it on the hadoop lib directory? Or >>> somewhere on the HBase structure? >>> >>> Thanks, >>> >>> JM >>> >>> 2012/10/29, Shrijeet Paliwal <[email protected]>: >>> > In line. >>> > >>> > On Mon, Oct 29, 2012 at 8:11 AM, Jean-Marc Spaggiari < >>> > [email protected]> wrote: >>> > >>> >> I'm replying to myself ;) >>> >> >>> >> I found "cleanup" and "setup" methods from the TableMapper table. So >>> >> I >>> >> think those are the methods I was looking for. I will init the >>> >> HTablePool there. Please let me know if I'm wrong. >>> >> >>> >> Now, I still have few other questions. >>> >> >>> >> 1) context.getCurrentValue() can throw a InterrruptedException, but >>> >> when can this occur? Is there a timeout on the Mapper side? Of it's >>> >> if >>> >> the region is going down while the job is running? >>> >> >>> > >>> > You do not need to call context.getCurrentValue(). The 'value' >>> > argument >>> to >>> > map method[1] has the information you are looking for. >>> > >>> > >>> >> 2) How can I pass parameters to the Map method? Can I use >>> >> job.getConfiguration().put to add some properties there, can get them >>> >> back in context.getConfiguration.get? >>> >> >>> > >>> > Yes, thats how it is done. >>> > >>> > >>> >> 3) What's the best way to log results/exceptions/traces from the map >>> >> method? >>> >> >>> > >>> > In most cases, you'll have mapper and reducer classes as nested static >>> > classes within some enclosing class. You can get handle to the Logger >>> from >>> > the enclosing class and do your usual LOG.info, LOG.warn yada yada. >>> > >>> > Hope it helps. >>> > >>> > [1] map(KEYIN key, *VALUEIN value*, Context context) >>> > >>> >> >>> >> I will search on my side, but some help will be welcome because it >>> >> seems there is not much documentation when we start to dig a bit :( >>> >> >>> >> JM >>> >> >>> >> 2012/10/27, Jean-Marc Spaggiari <[email protected]>: >>> >> > Hi, >>> >> > >>> >> > I'm thinking about my firs MapReduce class and I have some >>> >> > questions. >>> >> > >>> >> > The goal of it will be to move some rows from one table to another >>> >> > one >>> >> > based on the timestamp only. >>> >> > >>> >> > Since this is pretty new for me, I'm starting from the RowCounter >>> >> > class to have a baseline. >>> >> > >>> >> > There are few things I will have to update. First, the >>> >> > createSumittableJob method to get timestamp range instead of key >>> >> > range, and "play2 with the parameters. This part is fine. >>> >> > >>> >> > Next, I need to update the map method, and this is where I have >>> >> > some >>> >> > questions. >>> >> > >>> >> > I'm able to find the timestamp of all the cf:c from the >>> >> > context.getCurrentValue() method, that's fine. Now, my concern is >>> >> > on >>> >> > the way to get access to the table to store this field, and the >>> >> > table >>> >> > to delete it. Should I instantiate an HTable for the source table, >>> >> > and >>> >> > execute and delete on it, then do an insert on another HTable >>> >> > instance? Should I use an HTablePool? Also, since I’m already on >>> >> > the >>> >> > row, can’t I just mark it as deleted instead of calling a new >>> >> > HTable? >>> >> > >>> >> > Also, instead of calling the delete and put one by one, I would >>> >> > like >>> >> > to put them on a list and execute it only when it’s over 10 >>> >> > members. >>> >> > How can I make sure that at the end of the job, this is flushed? >>> >> > Else, >>> >> > I will lose some operations. Is there a kind of “dispose” method >>> >> > called on the region when the job is done? >>> >> > >>> >> > Thanks, >>> >> > >>> >> > JM >>> >> > >>> >> >>> > >>> >> >
