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Help with batch_mutate and composite keys

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Started 10 months ago by lilyevsky
Latest reply from p0pgun
This topic is not a support question

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lilyevsky
Member

My table has a composite key (let say, two ascii elements), and I am trying to use batch_mutate for the bulk load.
The argument for the method, mutation_map, is a map where the key is the key to the column family. Since my key is composite, I created it by concatenating ByteBuffer representations of the two components.
When i am trying to execute the batch_mutate method, I am getting exception:

Exception in thread "main" InvalidRequestException(why:Not enough bytes to read value of component 0)
at org.apache.cassandra.thrift.Cassandra$batch_mutate_result.read(Cassandra.java:20253)
at org.apache.thrift.TServiceClient.receiveBase(TServiceClient.java:78)
at org.apache.cassandra.thrift.Cassandra$Client.recv_batch_mutate(Cassandra.java:922)
at org.apache.cassandra.thrift.Cassandra$Client.batch_mutate(Cassandra.java:908)
at com.moon.cassandra.CassandraAccess.executeBatch(CassandraAccess.java:256)
at com.moon.cql.BatchTest.main(BatchTest.java:40)

What does this mean?
What am I doing wrong? Is it even possible to have composite key and use batch_mutate?

Thanks,

Leonid

Posted 10 months ago #
p0pgun
Member

Hi Leonid.

I'm also fairly new to Cassandra (~3 months), but this is an error I've ran into several times when programmatically working with composite keys. Your problem is that composite keys in cassandra are not simply concatenation of ByteBuffer of the components; cassandra composite keys use a specific format for the byte buffer.

Refer to CompositeTool.java here: http://www.jointhegrid.com/highperfcassandra/

Posted 9 months ago #

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