Alex Liu, of the Datastax Cassandra Developer Center, recently blogged about Cassandra's ability to support column TTL (time to live). He describes how Column TTL works, as well as how DSE search supports column TTL. Here's what he has to say about the future - you can read the original post here:
Good Practice to Set TTL Index Rebuilding Parameters
TTL index rebuilding does consume resources, e.g. cpu, memory and read Cassandra column families. You can make the re-indexing frequency to a longer time if there’s not much TTL data in Cassandra column families. For common use case, you need check the frequency of your compaction, and assign the re-indexing frequency to short than compaction frequency and match the re-indexing frequency to your business requirement.
We may make TTL re-indexing per column family, and expose it to the administration page, so we can tune it for each column family. We may have a per index TTL which can be set through solr restful API. I believe those enhancement will be available in the feature.
We may also make Cassandra to support PUSH, so it can automatically re-index the data when column expired. Another thought is to have a row base TTL.