Hi Ted, Thank you for your reply. You are right, the ticket has not been closed yet. At this point, I am mainly trying to understand how MultiTableInputCollection can be used to do Joins between HBase tables, if possible with an example.
Thanks, /David On Tue, Jul 17, 2012 at 11:07 PM, Ted Yu <[email protected]> wrote: > If my memory is correct, there're a few items that Stack pointed out which > are still outstanding for > HBASE-3996<https://issues.apache.org/jira/browse/HBASE-3996> > . > > Cheers > > On Tue, Jul 17, 2012 at 1:39 PM, David Koch <[email protected]> wrote: > > > Hello, > > > > I came across this ticket for multiple table scans via and their use in > > Map/Reduce jobs: > > > > https://issues.apache.org/jira/browse/HBASE-3996 > > https://reviews.apache.org/r/4411/diff/7/ > > > > There is a patch for this now and it is mentioned in the comments that > the > > functionality could be useful for doing joins as part of a map reduce. > > Could someone briefly explain how this works? I am interested in doing > > joins between 2 tables on rowkeys. > > > > If I append both tables to the newly added MultiTableInputCollection > > instance and use that in a Map/Reduce - would map(<rowkey>, <value>) only > > be called once per unique <rowkey> with <value> containing 2 value sets > if > > the key was found in both tables? > > > > If there exist any practical examples for doing joins on HBase tables I'd > > appreciate a link. Also, I am using Hbase client 0.90.6-cdh3u4, is the > > patch applicable to this version of HBase at all? > > > > Thank you, > > > > /David > > >
