With these basic modifications (see the patch) and the following tickets, the Elassandra project (see https://github.com/strapdata/elassandra) could be an Elasticsearch plugin for Cassandra.
- CASSANDRA-12837 Add multi-threaded support to nodetool rebuild_index.
- CASSANDRA-13267 Add CQL functions.
CASSANDRA-13268Allow to create custom secondary index on static columns.
- CASSANDRA-13269 Snapshot support for custom secondary indices