Alon, We came to the same conclusion regarding secondary indexes, and instead of using them we implemented our own wide-row indexing capability and open-sourced it.
Its available here: https://github.com/hmsonline/cassandra-indexing We still have challenges rebuilding indexes, etc. It doesn't address all of your concerns, but I tried to capture the motivation behind our implementation here: http://brianoneill.blogspot.com/2012/03/cassandra-indexing-good-bad-and-ugl y.html -brian -- Brian O'Neill Lead Architect, Software Development Health Market Science | 2700 Horizon Drive | King of Prussia, PA 19406 p: 215.588.6024 www.healthmarketscience.com On 7/26/12 2:05 PM, "Alon Pilberg" <alo...@taboola.com> wrote: >Hello, >My company is working on transition of our relational data model to >Cassandra. Naturally, one of the basic demands is to have secondary >indexes to answer queries quickly according to the application's >needs. >After looking at Cassandra's native support for secondary indexes, we >decided not to use them due to the poor performance for >high-cardinality values. Instead, we decide to implement secondary >indexes manually. >Some search led us to >http://www.anuff.com/2010/07/secondary-indexes-in-cassandra.html which >details a schema for such indexes. However, the method employed there >specifically adds an index entries column family, whereas it seems >like only 2 CFs are needed - one for the items and one for the indexes >(assuming one has access to both old and new values when updating an >item). The article actually mentioned that this is indeed not the >obvious solution, "for a number of reasons related to Cassandra's >model of eventual consistency ... will not reliably work" and "it's a >really good idea to make sure you understand why this CF is >necessary". However, no additional information is provided on what >might be a critical issue, as dealing with corrupt indexes in a large >production environment is surely to be a nightmare. >What are the community's thoughts on this matter? Given the writer's >credentials in the Cassandra realm, specifically regarding indexes, >I'm inclined not to ignore his remarks. >References to a document / system that implement similar indexes would >be greatly appreciated as well. > >- alon
