agate created HIVE-5172:
---------------------------

             Summary: TUGIContainingTransport returning null transport, causing 
intermittent SocketTimeoutException on hive client and NullPointerException in 
TUGIBasedProcessor on the server
                 Key: HIVE-5172
                 URL: https://issues.apache.org/jira/browse/HIVE-5172
             Project: Hive
          Issue Type: Bug
          Components: Metastore
    Affects Versions: 0.9.0
            Reporter: agate


We are running into frequent problem using HCatalog 0.4.1 (Hive Metastore 
Server 0.9) where we get connection reset or connection timeout errors on the 
client and NullPointerException in TUGITransport on the server. 



hive client logs:
=================

org.apache.thrift.transport.TTransportException: 
java.net.SocketTimeoutException: Read timed out
at 
org.apache.thrift.transport.TIOStreamTransport.read(TIOStreamTransport.java:129)
at org.apache.thrift.transport.TTransport.readAll(TTransport.java:84)
at org.apache.thrift.protocol.TBinaryProtocol.readAll(TBinaryProtocol.java:378)
at org.apache.thrift.protocol.TBinaryProtocol.readI32(TBinaryProtocol.java:297)
at 
org.apache.thrift.protocol.TBinaryProtocol.readMessageBegin(TBinaryProtocol.java:204)
at org.apache.thrift.TServiceClient.receiveBase(TServiceClient.java:69)
at 
org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$Client.recv_set_ugi(ThriftHiveMetastore.java:2136)
at 
org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$Client.set_ugi(ThriftHiveMetastore.java:2122)
at 
org.apache.hadoop.hive.metastore.HiveMetaStoreClient.openStore(HiveMetaStoreClient.java:286)
at 
org.apache.hadoop.hive.metastore.HiveMetaStoreClient.open(HiveMetaStoreClient.java:197)
at 
org.apache.hadoop.hive.metastore.HiveMetaStoreClient.<init>(HiveMetaStoreClient.java:157)
at org.apache.hadoop.hive.ql.metadata.Hive.createMetaStoreClient(Hive.java:2092)
at org.apache.hadoop.hive.ql.metadata.Hive.getMSC(Hive.java:2102)
at org.apache.hadoop.hive.ql.metadata.Hive.getTable(Hive.java:888)
at org.apache.hadoop.hive.ql.metadata.Hive.getTable(Hive.java:830)
at 
org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.getMetaData(SemanticAnalyzer.java:954)
at 
org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.analyzeInternal(SemanticAnalyzer.java:7524)
at 
org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer.analyze(BaseSemanticAnalyzer.java:243)
at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:431)
at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:336)
at org.apache.hadoop.hive.ql.Driver.run(Driver.java:909)
at org.apache.hadoop.hive.cli.CliDriver.processLocalCmd(CliDriver.java:258)
at org.apache.hadoop.hive.cli.CliDriver.processCmd(CliDriver.java:215)
at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:406)
at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:341)
at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:642)
at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:557)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.RunJar.main(RunJar.java:156)
Caused by: java.net.SocketTimeoutException: Read timed out
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:129)
at 
org.apache.thrift.transport.TIOStreamTransport.read(TIOStreamTransport.java:127)
... 31 more



hive metastore server logs:
===============================

2013-07-26 06:34:52,853 ERROR server.TThreadPoolServer 
(TThreadPoolServer.java:run(182)) - Error occurred during processing of message.
java.lang.NullPointerException
        at 
org.apache.hadoop.hive.metastore.TUGIBasedProcessor.setIpAddress(TUGIBasedProcessor.java:183)
        at 
org.apache.hadoop.hive.metastore.TUGIBasedProcessor.process(TUGIBasedProcessor.java:79)
        at 
org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:176)
at 
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at 
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)


Adding some extra debug log messages in TUGIBasedProcessor, noticed that the 
TUGIContainingTransport is null which results in NullPointerException on the 
server.

Further drilling into TUGIContainingTransport noticed that getTransport() 
returns a null which causes the above 
error. 

Further corelating with GC logs observed that that error always hits when the 
CMS GC has just kicked in 
(but does not happen after every GC)



Put some debugging code in TUGIContainingTransport.getTransport() and I tracked 
it down to 

@Override
public TUGIContainingTransport getTransport(TTransport trans) {

      // UGI information is not available at connection setup time, it will be 
set later
      // via set_ugi() rpc.
      transMap.putIfAbsent(trans, new TUGIContainingTransport(trans));

      //return transMap.get(trans); //<-change

      TUGIContainingTransport retTrans = transMap.get(trans);

      if ( retTrans == null ) {
             LOGGER.error ("cannot find transport that was in map !!")
             return retTrans;
       }  else {
             LOGGER.debug ("found transport in map")
             return retTrans;    
       }
}

When we run this in our test environment, see that we run into the problem just 
after GC runs,
and "cannot find transport that was in the map!!" message gets logged.

Could the GC be collecting entries from transMap, just before the we get it 

Tried a minor change which seems to work

public TUGIContainingTransport getTransport(TTransport trans) {

   TUGIContainingTransport retTrans = transMap.get(trans);

    if ( retTrans == null ) {
      // UGI information is not available at connection setup time, it will be 
set later
      // via set_ugi() rpc.
      transMap.putIfAbsent(trans, retTrans);
    }
   return retTrans;
}


My questions for hive and  thrift experts

1.) Do we need to use a ConcurrentMap
ConcurrentMap<TTransport, TUGIContainingTransport> transMap = new 
MapMaker().weakKeys().weakValues().makeMap();
It does use == to compare keys (which might be the problem), also in this case 
we cant rely on the trans to be always there in the transMap, even after a put, 
so in that case change above probably makes sense

2.) Is it better idea to use WeakHashMap with WeakReference value instead ? 
(was looking at org.apache.thrift.transport.TSaslServerTransport, especially 
change made by THRIFT-1468 as an example)

e.g.

private static Map<TTransport, WeakReference<TUGIContainingTransport>> transMap 
= Collections.synchronizedMap(new WeakHashMap<TTransport, 
WeakReference<TUGIContainingTransport>>());

getTransport() would be something like

public TUGIContainingTransport getTransport(TTransport trans) {
      WeakReference<TUGIContainingTransport> ret = transMap.get(trans);
      if (ret == null || ret.get() == null) {
        ret = new WeakReference<TUGIContainingTransport>(new 
TUGIContainingTransport(trans));  
        transMap.put(trans, ret); // No need for putIfAbsent().
                                   // Concurrent calls to getTransport() will 
pass in different TTransports.
      }
      return ret.get();
}

3.) Is it absolutely essential that successive calls to get getTransport() need 
to retrieve the same TUGIContainingTransport object or its ok to create a new 
one, if its not available in the map ?

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Reply via email to