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Posted to user@hbase.apache.org by "Buttler, David" <bu...@llnl.gov> on 2010/01/12 22:05:12 UTC

NPE in TableInputFormatBase$TableRecordReader.restart() (line 110)

Hi All,
I am trying to set up a map-reduce job over my hbase installation and I am running into an error that puzzles me:
MapAttempt TASK_TYPE="MAP" TASKID="task_201001061749_0006_m_000004" TASK_ATTEMPT_ID="attempt_201001061749_0006_m_000004_2" TASK_STATUS="FAILED" FINISH_TIME="1263318756976" HOSTNAME="compute-0-9\.local" ERROR="java\.lang\.NullPointerException
        at org\.apache\.hadoop\.hbase\.mapreduce\.TableInputFormatBase$TableRecordReader\.restart(TableInputFormatBase\.java:110)
        at org\.apache\.hadoop\.hbase\.mapreduce\.TableInputFormatBase$TableRecordReader\.init(TableInputFormatBase\.java:119)
        at org\.apache\.hadoop\.hbase\.mapreduce\.TableInputFormatBase\.createRecordReader(TableInputFormatBase\.java:262)
        at org\.apache\.hadoop\.mapred\.MapTask\.runNewMapper(MapTask\.java:551)
        at org\.apache\.hadoop\.mapred\.MapTask\.run(MapTask\.java:305)
        at org\.apache\.hadoop\.mapred\.Child\.main(Child\.java:170)


versions:
hadoop 0.20.1
hbase 0.20.2
zookeeper 3.2.1


Looking at the hbase source code suggests that for some reason the htable field is not being initialized.  However, according to my console, I get through approximately 26% of the map tasks and 9% of the reduce tasks before it fails [although I am not sure how accurate that is as I don't see any changes to my hbase table].

I get this result with both my own code an running org.apache.hadoop.hbase.mapreduce.RowCounter

Any suggestions?
Dave

Re: NPE in TableInputFormatBase$TableRecordReader.restart() (line 110)

Posted by stack <st...@duboce.net>.
On Tue, Jan 12, 2010 at 1:05 PM, Buttler, David <bu...@llnl.gov> wrote:

>
> Looking at the hbase source code suggests that for some reason the htable
> field is not being initialized.  However, according to my console, I get
> through approximately 26% of the map tasks and 9% of the reduce tasks before
> it fails [although I am not sure how accurate that is as I don't see any
> changes to my hbase table].
>
> I get this result with both my own code an running
> org.apache.hadoop.hbase.mapreduce.RowCounter
>


My guess is that its something to do with your environment -- that and then
we're not handling whatever it is gracefully.  RowCounter at least works for
me.   Its odd that you are 26% of the ways through the map task when this
happens (Is this so w/ rowcounter?).  That would almost imply the problem
transient since a bunch of map tasks have completed already.  What if you
added a bit of debug to TIF#setConf and see what its passing into setHTable.

St.Ack