Slides from a Cassandra talk at Mountain View

Whats not mentioned in the slide was Gary’s reference to the number of key changes in 0.7 version of Cassandra. He thinks beta would be out in a month and that it will address a lot of issues which is currently keeping a lot of Cassandra users away. Few interesting points

  • 0.5, 0.6 use the same version of SSTABLE (to store data on disk), but 0.7 changes that. This will require some kind of migration if 0.7 doesn’t support reading old versions of SSTABLE.
  • until now, one needs 50% disk space available (free) to do compaction operation. This might improve with 0.7
  • 0.7 would probably have more support for avro (instead of thrift). He wonders why thrift hasn’t caught on
  • Vector clocks coming..
  • altering keyspace and column families is not possible on a live system today… might change with future version
  • Compression is being thought about…

He strongly urged users to use client libraries which abstract out the internals of Cassandra’s internal workings. It was convincing enough for me to investigate a move from cassandra’s java lib, to “hector” for my java application.