As a DataStax customer and currently/still in a Astyanax/Thrift-based scenario, I would like to sincerely ask the Cassandra project to investigate including the newer library in Cassandra 2.0x already. I guess 3.0 is a long-road ahead until it is ready for production. As far as I can see is that Cassandra 2.0.11 resp. at least DSE 4.5.3 is using 0.9.1 so an upgrade to 0.9.2 might not be that tricky. I must admit that I haven't investigated the code or library dependency changes in 0.9.2, but I can say that a simple drop-in replacement of 0.9.2 in our DSE 4.5.3 based loadtest environment works without troubles. Attached a screen of the Cassandra heap improvement in our tests simply by replacing thrift 0.9.1 with 0.9.2.
This is in an environment with 3 of our servers hitting a 6 node EC2 (m1.xlarge) based Cassandra cluster with an Astyanax max connection pool setting of 50 per Cassandra node, thus max. 150 (3 * 50) connections per Cassandra nodes, where each connection is represented by a TFramedTransport instance on the Cassandra side which can grow dramatically depending on the Client/Astyanax single read request size.