But how would the comparator have access to the job config?
On Sat, Aug 31, 2013 at 2:38 AM, Shahab Yunus <shahab.yu...@gmail.com>wrote: > I think you have to override/extend the Comparator to achieve that, > something like what is done in Secondary Sort? > > Regards, > Shahab > > > On Fri, Aug 30, 2013 at 9:01 PM, Adrian CAPDEFIER > <chivas314...@gmail.com>wrote: > >> Howdy, >> >> I apologise for the lack of code in this message, but the code is fairly >> convoluted and it would obscure my problem. That being said, I can put >> together some sample code if really needed. >> >> I am trying to pass some metadata between the map & reduce steps. This >> metadata is read and generated in the map step and stored in the job >> config. It also needs to be recreated on the reduce node before the key/ >> value fields can be read in the readFields function. >> >> I had assumed that I would be able to override the Reducer.setup() >> function and that would be it, but apparently the readFields function is >> called before the Reducer.setup() function. >> >> My question is what is any (the best) place on the reduce node where I >> can access the job configuration/ context before the readFields function is >> called? >> >> This is the stack trace: >> >> at >> org.apache.hadoop.io.WritableComparator.compare(WritableComparator.java:103) >> at >> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.compare(MapTask.java:1111) >> at >> org.apache.hadoop.util.QuickSort.sortInternal(QuickSort.java:70) >> at org.apache.hadoop.util.QuickSort.sort(QuickSort.java:59) >> at >> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.sortAndSpill(MapTask.java:1399) >> at >> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.flush(MapTask.java:1298) >> at >> org.apache.hadoop.mapred.MapTask$NewOutputCollector.close(MapTask.java:699) >> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:766) >> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370) >> at org.apache.hadoop.mapred.Child$4.run(Child.java:255) >> at java.security.AccessController.doPrivileged(Native Method) >> at javax.security.auth.Subject.doAs(Subject.java:415) >> at >> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1149) >> at org.apache.hadoop.mapred.Child.main(Child.java:249) >> >> >
