Re: Unknown Scanner Exception

Mon, 11 Aug 2008 15:32:24 -0700 

Hi J-D,
I watched as one of the map tasks completed successfully. Another one was launched as a child of the second MR task. then I get the Unknown Scanner Exception: org.apache.hadoop.hbase.UnknownScannerException: org.apache.hadoop.hbase.UnknownScannerException: Name: -463563612898654250 at org .apache .hadoop.hbase.regionserver.HRegionServer.next(HRegionServer.java:1115) 
        at sun.reflect.GeneratedMethodAccessor4.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$Server.call(HbaseRPC.java:473)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:896)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun .reflect .NativeConstructorAccessorImpl .newInstance(NativeConstructorAccessorImpl.java:39) at sun .reflect .DelegatingConstructorAccessorImpl .newInstance(DelegatingConstructorAccessorImpl.java:27) 
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at org .apache .hadoop .hbase .RemoteExceptionHandler .decodeRemoteException(RemoteExceptionHandler.java:82) at org.apache.hadoop.hbase.client.HConnectionManager $TableServers.getRegionServerWithRetries(HConnectionManager.java:885) at org.apache.hadoop.hbase.client.HTable $ClientScanner.next(HTable.java:1321) at org.apache.hadoop.hbase.mapred.TableInputFormatBase $TableRecordReader.next(TableInputFormatBase.java:202) at org.apache.hadoop.hbase.mapred.TableInputFormatBase $TableRecordReader.next(TableInputFormatBase.java:84) at org.apache.hadoop.mapred.MapTask $TrackedRecordReader.next(MapTask.java:158) 
        at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:45)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:219)
at org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java: 2124) I checked the table in the UI but it still only shows 4 regions. Up to this point, I have not been able to get this process to complete so I think there is more to this than just a failing task. After re- running the task, I continued to get the same error.
By creating an intermediary table, The map/reduce process completed successfully. 

Thanks again for your help.
Dru

On Aug 11, 2008, at 1:09 PM, Jean-Daniel Cryans wrote:


Dru,
Using another table, but we're still not so sure that it does something bad apart from restarting the Map task (see the discussion between sebastien and 
stack in 810).

J-D
On Mon, Aug 11, 2008 at 3:58 PM, Dru Jensen <[EMAIL PROTECTED]> wrote: 


J-D,

I have 4 regions for this table all on the same server.
It looks like it may be related. I have started another test and will 
verify.
Is there a fix for this issue or should I create a intermediary table for 
now?

thanks,
Dru


On Aug 11, 2008, at 11:54 AM, Jean-Daniel Cryans wrote:

Dru,
Apart from doing a 'tail' on all your region server logs, watching your number of regions in the web UI. How many regions do you have currently in 
your table?

J-D
On Mon, Aug 11, 2008 at 2:52 PM, Dru Jensen <[EMAIL PROTECTED]> wrote: 

Hi J-D,
I am writing to the same table that I'm scanning, however I get this 
often
and would be surprised if its caused by a split.

How can I determine if a split is occurring?

thanks,
Dru


On Aug 11, 2008, at 11:35 AM, Jean-Daniel Cryans wrote:

Dru,



Can you tell me if your situation is the same on as in
https://issues.apache.org/jira/browse/HBASE-810

Thx,

J-D

On Mon, Aug 11, 2008 at 2:35 PM, Dru Jensen <[EMAIL PROTECTED]>
wrote:

What causes the following error?  It's coming from the


TableInputFormatBase
class.  It seems to be fairly random for me.

From what I've read so far, its related to a timeout error?  I
verified
my
map task doesn't take long to process. Anything else that may cause 
this?

org.apache.hadoop.hbase.UnknownScannerException:
org.apache.hadoop.hbase.UnknownScannerException: Name:
4797186499140551292
  at
org .apache .hadoop .hbase.regionserver.HRegionServer.next(HRegionServer.java:1115) 
  at sun.reflect.GeneratedMethodAccessor4.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$Server.call(HbaseRPC.java: 473) 
  at org.apache.hadoop.ipc.Server$Handler.run(Server.java:896)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native 
Method)
  at
sun .reflect .NativeConstructorAccessorImpl .newInstance(NativeConstructorAccessorImpl.java:39) 
  at
sun .reflect .DelegatingConstructorAccessorImpl .newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java: 513) 
  at
org .apache .hadoop .hbase .RemoteExceptionHandler .decodeRemoteException(RemoteExceptionHandler.java:82) 
  at
org.apache.hadoop.hbase.client.HConnectionManager $ TableServers.getRegionServerWithRetries(HConnectionManager.java: 885) 
  at
org.apache.hadoop.hbase.client.HTable $ClientScanner.next(HTable.java:1321) 
  at
org.apache.hadoop.hbase.mapred.TableInputFormatBase $TableRecordReader.next(TableInputFormatBase.java:202) 
  at
org.apache.hadoop.hbase.mapred.TableInputFormatBase $TableRecordReader.next(TableInputFormatBase.java:84) 
  at
org.apache.hadoop.mapred.MapTask $TrackedRecordReader.next(MapTask.java:158) 
  at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:45)
  at org.apache.hadoop.mapred.MapTask.run(MapTask.java:219)
  at
org.apache.hadoop.mapred.TaskTracker $Child.main(TaskTracker.java:2124)

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