To help us more easily correlate line numbers, can you tell us the version
of HBase you're using ?
Thanks
On Tue, Feb 5, 2013 at 10:39 AM, Bing Li <lbl...@gmail.com> wrote:
> Dear all,
>
> To raise the performance of writing data into HBase, the
> "synchronized" is removed from the writing method.
>
> But after "synchronized" is removed from the method of writing, I get
> the following exceptions when reading. Before the removal, no such
> exceptions.
>
> Could you help me how to solve it?
>
> Thanks so much!
>
> Best wishes,
> Bing
>
> Feb 6, 2013 12:21:31 AM
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection run
> WARNING: Unexpected exception receiving call responses
> java.lang.NullPointerException
> at
> org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:521)
> at
> org.apache.hadoop.hbase.io.HbaseObjectWritable.readFields(HbaseObjectWritable.java:297)
> at
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.receiveResponse(HBaseClient.java:593)
> at
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.run(HBaseClient.java:505)
> Feb 6, 2013 12:21:31 AM
> org.apache.hadoop.hbase.client.ScannerCallable close
> WARNING: Ignore, probably already closed
> java.io.IOException: Call to greatfreeweb/127.0.1.1:60020
> failed on local exception: java.io.IOException: Unexpected exception
> receiving call responses
> at
> org.apache.hadoop.hbase.ipc.HBaseClient.wrapException(HBaseClient.java:934)
> at
> org.apache.hadoop.hbase.ipc.HBaseClient.call(HBaseClient.java:903)
> at
> org.apache.hadoop.hbase.ipc.WritableRpcEngine$Invoker.invoke(WritableRpcEngine.java:150)
> at $Proxy6.close(Unknown Source)
> at
> org.apache.hadoop.hbase.client.ScannerCallable.close(ScannerCallable.java:112)
> at
> org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:74)
> at
> org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:39)
> at
> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionServerWithRetries(HConnectionManager.java:1325)
> at
> org.apache.hadoop.hbase.client.HTable$ClientScanner.nextScanner(HTable.java:1167)
> at
> org.apache.hadoop.hbase.client.HTable$ClientScanner.next(HTable.java:1296)
> at
> org.apache.hadoop.hbase.client.HTable$ClientScanner$1.hasNext(HTable.java:1356)
> at
> com.greatfree.hbase.rank.NodeRankRetriever.LoadNodeGroupNodeRankRowKeys(NodeRankRetriever.java:348)
> at
> com.greatfree.ranking.PersistNodeGroupNodeRanksThread.run(PersistNodeGroupNodeRanksThread.java:29)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:662) Caused by:
> java.io.IOException: Unexpected exception receiving call responses
> at
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.run(HBaseClient.java:509)
> Caused by: java.lang.NullPointerException
> at
> org.apache.hadoop.hbase.io.HbaseObjectWritable.readObject(HbaseObjectWritable.java:521)
> at
> org.apache.hadoop.hbase.io.HbaseObjectWritable.readFields(HbaseObjectWritable.java:297)
> at
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.receiveResponse(HBaseClient.java:593)
> at
> org.apache.hadoop.hbase.ipc.HBaseClient$Connection.run(HBaseClient.java:505)
>
> The writing method is as follows.
>
>
> // The "synchronized" is removed to raise the performance.
> // public synchronized void AddNodeViewGroupNodeRanks(String
> hostNodeKey, String groupKey, int timingScale, Map<String, Double>
> groupNodeRankMap)
>
> public void AddNodeViewGroupNodeRanks(String hostNodeKey, String
> groupKey, int timingScale, Map<String, Double> groupNodeRankMap)
> {
> List<Put> puts = new ArrayList<Put>();
> Put hostNodeKeyPut;
> Put groupKeyPut;
> Put timingScalePut;
> Put nodeKeyPut;
> Put rankPut;
>
> byte[] groupNodeRankRowKey;
>
> for (Map.Entry<String, Double> nodeRankEntry :
> groupNodeRankMap.entrySet())
> {
> groupNodeRankRowKey = Bytes.toBytes(...);
>
> hostNodeKeyPut = new Put(groupNodeRankRowKey);
> hostNodeKeyPut.add(...);
> puts.add(hostNodeKeyPut);
> ......
>
> rankPut = new Put(groupNodeRankRowKey);
> rankPut.add(...);
> puts.add(rankPut);
> }
>
> try
> {
> this.rankTable.put(puts);
> }
> catch (IOException e)
> {
> e.printStackTrace();
> }
> }
>
>
> The reading method that causes the exceptions is as follows.
>
> public Set<String> LoadNodeGroupNodeRankRowKeys(String
> hostNodeKey, String groupKey, int timingScale)
> {
> List<Filter> nodeGroupFilterList = new ArrayList<Filter>();
>
> SingleColumnValueFilter hostNodeKeyFilter = new
> SingleColumnValueFilter(...);
> hostNodeKeyFilter.setFilterIfMissing(true);
> nodeGroupFilterList.add(hostNodeKeyFilter);
>
> ......
>
> FilterList nodeGroupFilter = new
> FilterList(nodeGroupFilterList);
> Scan scan = new Scan();
> scan.setFilter(nodeGroupFilter);
> scan.setCaching(Parameters.CACHING_SIZE);
> scan.setBatch(Parameters.BATCHING_SIZE);
>
> Set<String> rowKeySet = Sets.newHashSet();
> try
> {
> ResultScanner scanner =
> this.rankTable.getScanner(scan);
>
> // EXCEPTIONS are raised at the following line.
> for (Result result : scanner)
> {
> for (KeyValue kv : result.raw())
> {
> rowKeySet.add(Bytes.toString(kv.getRow()));
> break;
> }
> }
> scanner.close();
> }
> catch (IOException e)
> {
> e.printStackTrace();
> }
> return rowKeySet;
> }
>
