http://www.datastax.com/support-forums/topic/help-with-batch_mutate-and-composite-keys Software, Support, and Training for Apache Cassandra en-US Mon, 20 May 2013 03:44:08 +0000 http://bbpress.org/?v=1.0.3 q http://www.datastax.com/support-forums/search.php http://www.datastax.com/support-forums/topic/help-with-batch_mutate-and-composite-keys#post-4479 Tue, 31 Jul 2012 22:44:11 +0000 p0pgun 4479@http://www.datastax.com/support-forums/ <p>Hi Leonid.</p> <p>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.</p> <p>Refer to CompositeTool.java here: <a href="http://www.jointhegrid.com/highperfcassandra/" rel="nofollow">http://www.jointhegrid.com/highperfcassandra/</a> </p> http://www.datastax.com/support-forums/topic/help-with-batch_mutate-and-composite-keys#post-2719 Thu, 05 Jul 2012 18:22:47 +0000 lilyevsky 2719@http://www.datastax.com/support-forums/ <p>My table has a composite key (let say, two ascii elements), and I am trying to use batch_mutate for the bulk load.<br /> 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.<br /> When i am trying to execute the batch_mutate method, I am getting exception:</p> <p>Exception in thread "main" InvalidRequestException(why:Not enough bytes to read value of component 0)<br /> at org.apache.cassandra.thrift.Cassandra$batch_mutate_result.read(Cassandra.java:20253)<br /> at org.apache.thrift.TServiceClient.receiveBase(TServiceClient.java:78)<br /> at org.apache.cassandra.thrift.Cassandra$Client.recv_batch_mutate(Cassandra.java:922)<br /> at org.apache.cassandra.thrift.Cassandra$Client.batch_mutate(Cassandra.java:908)<br /> at com.moon.cassandra.CassandraAccess.executeBatch(CassandraAccess.java:256)<br /> at com.moon.cql.BatchTest.main(BatchTest.java:40)</p> <p>What does this mean?<br /> What am I doing wrong? Is it even possible to have composite key and use batch_mutate?</p> <p>Thanks,</p> <p>Leonid </p>