Rob Timpe created CASSANDRA-5529: ------------------------------------ Summary: ColumnFamilyRecordReader fails for large datasets Key: CASSANDRA-5529 URL: https://issues.apache.org/jira/browse/CASSANDRA-5529 Project: Cassandra Issue Type: Bug Components: Hadoop Affects Versions: 1.2.4, 1.1.11 Reporter: Rob Timpe
When running mapreduce jobs that read directly from cassandra, the job will sometimes fail with an exception like this: java.lang.RuntimeException: com.rockmelt.org.apache.thrift.TException: Message length exceeded: 40 at org.apache.cassandra.hadoop.ColumnFamilyRecordReader$StaticRowIterator.maybeInit(ColumnFamilyRecordReader.java:400) at org.apache.cassandra.hadoop.ColumnFamilyRecordReader$StaticRowIterator.computeNext(ColumnFamilyRecordReader.java:406) at org.apache.cassandra.hadoop.ColumnFamilyRecordReader$StaticRowIterator.computeNext(ColumnFamilyRecordReader.java:329) at com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:143) at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138) at org.apache.cassandra.hadoop.ColumnFamilyRecordReader.getProgress(ColumnFamilyRecordReader.java:109) at org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.getProgress(MapTask.java:522) at org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.nextKeyValue(MapTask.java:547) at org.apache.hadoop.mapreduce.MapContext.nextKeyValue(MapContext.java:67) at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:143) at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:771) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:375) at org.apache.hadoop.mapred.Child$4.run(Child.java:255) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:396) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1132) at org.apache.hadoop.mapred.Child.main(Child.java:249) Caused by: com.rockmelt.org.apache.thrift.TException: Message length exceeded: 40 at com.rockmelt.org.apache.thrift.protocol.TBinaryProtocol.checkReadLength(TBinaryProtocol.java:393) at com.rockmelt.org.apache.thrift.protocol.TBinaryProtocol.readBinary(TBinaryProtocol.java:363) at org.apache.cassandra.thrift.Column.read(Column.java:528) at org.apache.cassandra.thrift.ColumnOrSuperColumn.read(ColumnOrSuperColumn.java:507) at org.apache.cassandra.thrift.KeySlice.read(KeySlice.java:408) at org.apache.cassandra.thrift.Cassandra$get_range_slices_result.read(Cassandra.java:12422) at com.rockmelt.org.apache.thrift.TServiceClient.receiveBase(TServiceClient.java:78) at org.apache.cassandra.thrift.Cassandra$Client.recv_get_range_slices(Cassandra.java:696) at org.apache.cassandra.thrift.Cassandra$Client.get_range_slices(Cassandra.java:680) at org.apache.cassandra.hadoop.ColumnFamilyRecordReader$StaticRowIterator.maybeInit(ColumnFamilyRecordReader.java:362) ... 16 more In ColumnFamilyRecordReader#initialize, a TBinaryProtocol is created as follows: TTransport transport = ConfigHelper.getInputTransportFactory(conf).openTransport(socket, conf); TBinaryProtocol binaryProtocol = new TBinaryProtocol(transport, ConfigHelper.getThriftMaxMessageLength(conf)); client = new Cassandra.Client(binaryProtocol); But each time a call to cassandra is made, checkReadLength(int length) is called in TBinaryProtocol, which includes this: readLength_ -= length; if (readLength_ < 0) { throw new TException("Message length exceeded: " + length); } The result is that readLength_ is decreased each time, until it goes negative and exception is thrown. This will only happen if you're reading a lot of data and your split size is large (which is maybe why people haven't noticed it earlier). This happens regardless of whether you use wide row support. I'm not sure what the right fix is. It seems like you could either reset the length of TBinaryProtocol after each call or just use a new TBinaryProtocol each time. -- 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