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Posted to dev@gora.apache.org by "Lewis John McGibbney (JIRA)" <ji...@apache.org> on 2012/09/22 15:02:07 UTC
[jira] [Commented] (GORA-170) Getting a BufferUnderflowException in
class CassandraColumn, method fromByteBuffer()
[ https://issues.apache.org/jira/browse/GORA-170?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13461146#comment-13461146 ]
Lewis John McGibbney commented on GORA-170:
-------------------------------------------
Hi Chris, nice one.
I began working on a trivial test case and will upload the patch once this is completed tomorrow when I get back to it. Thanks
> Getting a BufferUnderflowException in class CassandraColumn, method fromByteBuffer()
> ------------------------------------------------------------------------------------
>
> Key: GORA-170
> URL: https://issues.apache.org/jira/browse/GORA-170
> Project: Apache Gora
> Issue Type: Bug
> Components: storage-cassandra
> Affects Versions: 0.2.1
> Environment: Not sure environment matters for this one but Ubuntu
> Reporter: Chris Gerken
> Priority: Blocker
>
> When using CassandraStore and GoraMapper to retrieve data previously stored in Cassandra, a BufferUnderflowException is being thrown in method fromByteBuffer() in class CassandraColumn. This results in a complete failure of the hadoop job trying to use the Cassandra data.
> The problem seems to be caused by an invalid assumption in the (de) Serializer logic. Serializers assume that the bytes in a ByteBuffer to be deserialized start at offset 0 (zero) in the ByteBuffer's internal buffer. In fact, there are times when a ByteBuffer passed back from the Hector/Thrift API will have its data start at a non-zero offset in its buffer. When serializers are given these non-zero offset ByteBuffers an exception, usually BufferUnderflowException, is thrown.
> The suggested fix is to use the TbaseHelper class from Cassandra/Thrift:
> import org.apache.thrift.TBaseHelper;
> protected Object fromByteBuffer(Schema schema, ByteBuffer byteBuffer) {
> Object value = null;
> Serializer serializer = GoraSerializerTypeInferer.getSerializer(schema);
> if (serializer == null) {
> LOG.info("Schema is not supported: " + schema.toString());
> } else {
> ByteBuffer corrected = TBaseHelper.rightSize(byteBuffer);
> value = serializer.fromByteBuffer(corrected);
> }
> return value;
> }
>
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