It's usually because your scanner timed out, or because the region moved to a new server. You can see how it's handled in HTable.ClientScanner.next(). In any case you should see a message like "Scanner -8711007779313115048 lease expired" in some region server, then see when you get the exception. Check if it's the same region server, and the time between both.
J-D On Thu, Sep 16, 2010 at 9:29 AM, Ken Weiner <[email protected]> wrote: > Every time we run a map reduce job against data in HBase, we see > hundreds of UnknownScannerExceptions in the hbase log at ERROR level. > The job seems to complete fine and there are no other errors. Should > I be concerned with these UnknownScannerExceptions? Is this message > really more of a warning than an error? > > > > Example: > > > > 2010-09-16 09:20:52,398 ERROR > org.apache.hadoop.hbase.regionserver.HRegionServer: > org.apache.hadoop.hbase.UnknownScannerException: Name: -8711007779313115048 > at > org.apache.hadoop.hbase.regionserver.HRegionServer.next(HRegionServer.java:1880) > at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source) > at > sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) > at java.lang.reflect.Method.invoke(Method.java:597) > at org.apache.hadoop.hbase.ipc.HBaseRPC$Server.call(HBaseRPC.java:657) > at > org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:915) >
