Cassandra + Ruby

Hi,
I am new to cassandra and was trying to achieve some simple
operations like inserting data into cassandra. I am using cassandra gem
to achieve this.

client = Cassandra.new(‘tags_logs’, ‘ec2-xxx-xxx-xxx.com:9160’)

client.disable_node_auto_discovery!

client.add_column_family(Cassandra::ColumnFamily.new(:keyspace =>
‘tags_logs’, :name => ‘impressions’))

client.insert(:impressions, “10”, {‘screen_name’ => “john”}) #this
worked fine

client.get(:impressions, “10”) gives me => {“screen_name”=>“john”} as
expected.

Now when I try to do the following command it gives me error

client.insert(:impressions, “10”, {“123_sdfsfd_sdfsdf” => {“filename” =>
“x”, “line_count” => 10}})

This line throws an error -

TypeError: can’t convert Hash into String
from
/home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/thrift-0.7.0/lib/thrift/transport/framed_transport.rb:84:in
write' from /home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/thrift-0.7.0/lib/thrift/protocol/binary_protocol.rb:112:in write_string’
from
/home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/thrift-0.7.0/lib/thrift/client.rb:35:in
write' from /home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/thrift-0.7.0/lib/thrift/client.rb:35:in send_message’
from
/home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/cassandra-0.12.1/vendor/0.8/gen-rb/cassandra.rb:247:in
send_batch_mutate' from /home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/cassandra-0.12.1/vendor/0.8/gen-rb/cassandra.rb:242:in batch_mutate’
from
/home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/thrift_client-0.7.0/lib/thrift_client/abstract_thrift_client.rb:131:in
handled_proxy' from /home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/thrift_client-0.7.0/lib/thrift_client/abstract_thrift_client.rb:60:in batch_mutate’
from
/home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/cassandra-0.12.1/lib/cassandra/protocol.rb:7:in
_mutate' from /home/ubuntu/.rvm/gems/ruby-1.9.2-p290/gems/cassandra-0.12.1/lib/cassandra/cassandra.rb:459:in insert’
from (irb):21
from /home/ubuntu/.rvm/rubies/ruby-1.9.2-p290/bin/irb:16:in `’