This sounds like a version mismatch. Do you have the same version
installed on your servers and being pulled in your hadoop job?
On Mon, Oct 22, 2012 at 12:32 PM, J Mohamed Zahoor <[EMAIL PROTECTED]> wrote:
> Cool… But my map reduce doesn't even start…
> It fails while creating a record reader...
> The record reader fails in
> and throws a
> java.io.IOException: version not supported
> at org.apache.hadoop.hbase.client.Scan.readFields(Scan.java:558)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:723)
> 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.mapred.Child.main(Child.java:249)
> Basically the deserializing of Scan object from the conf is failing for
> some reason.
> On 22-Oct-2012, at 9:52 PM, Bryan Beaudreault <[EMAIL PROTECTED]>
> > I'm not on 0.94.1, but I've found a lot of situations that can cause
> > scanner timeouts and other scanner exceptions from M/R. The primary ones
> > probably still apply in later versions:
> > - Caching or batching set too high. If caching is set to, e.g. 1000,
> > and hbase.rpc.timeout is set to 30 seconds, it means you need to be
> able to
> > be able to process 1000 records in your mapper in under 30 seconds
> > the overhead of actually returning that many records). Otherwise the
> > mapper's next call to next() will throw a timeout.
> > - Similar to the above, this can happen if just the logic in your
> > is too heavy and taking too long. Just keep in mind that the
> > hbase.rpc.timeout can be triggered by the time between calls to next()
> > - hbase.rpc.timeout > hbase.regionserver.lease.period. If this is the
> > case, the RS will timeout first and kill the scan. Then your mapper
> > call next() and since the scan no longer exists will throw a scan/lease
> > exception.
> > - The filters on the mapper scan are causing too many rows to be
> > skipped, such that not enough rows can be collected to return within
> > timeout.
> > Hope this helps and/or is still accurate for your version.
> > On Mon, Oct 22, 2012 at 11:51 AM, J Mohamed Zahoor <[EMAIL PROTECTED]>
> >> I am using 0.94.1
> >> ./zahoor
> >> On 22-Oct-2012, at 9:17 PM, J Mohamed Zahoor <[EMAIL PROTECTED]> wrote:
> >>> Hi
> >>> I am facing a scanner exception like this when i run a mr job.
> >>> Both the input and output are hbase tables (different tables)…
> >>> This comes sporadically on some mapper and all other mappers runs
> >>> Even the failed mapper gets passed in the next attempt.
> >>> Any clue on what might be wrong?
> >>> java.lang.NullPointerException
> >>> at org.apache.hadoop.hbase.client.Scan.<init>(Scan.java:147)
> >>> at
> >>> at
> >>> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:731)
> >>> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
> >>> at org.apache.hadoop.mapred.Child$4.run(Child.java:255)