Rob Timpe created CASSANDRA-5529:
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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.
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