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 >
