Secondary indexes currently make some bad assumptions about the underlying indexes.
1. That they are always stored in other column families.
2. That there is a unique index per column
In the case of
CASSANDRA-2915 neither of these are true. The new api should abstract the search concepts and allow any search api to plug in.
Once the code is refactored and basically pluggable we can remove the IndexType enum and use class names similar to how we handle partitioners and comparators.
Basic api is to add a SecondaryIndexManager that handles different index types per CF and a SecondaryIndex base class that handles a particular type implementation.
This requires major changes to ColumnFamilyStore and Table.IndexBuilder