jaydeepkumar1984 opened a new pull request, #3548: URL: https://github.com/apache/cassandra/pull/3548
``` Cassandra keeps token-ownership in two separate caches. 1) Gossip cache 2) StorageService cache. These two caches could go out of sync, and if they go, it creates a catastrophic impact on workloads. Currently, no mechanism in Cassandra exist that detects and fixes these two caches. This PR improves these two caches. Details: As we know, Cassandra exchanges important topology and token-ownership-related details over Gossip. Cassandra internally maintains the following two separate caches that have the token ownership information maintained: 1) Gossip cache and 2) Storage Service cache. The first Gossip cache is updated on a node, followed by the storage service cache. In the hot path, ownership is calculated from the storage service cache. Since two separate caches maintain the same information, then inconsistencies are bound to happen. It could be very well feasible that the Gossip cache has up-to-date ownership of the Cassandra cluster, but the service cache does not, and in that scenario, inconsistent data will be served to the user. **Long-term solution** We are going with the long-term transactional metadata (https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-21) to handle such inconsistencies, and that’s the right thing to do. **Short-term solution** But CEP-21 might take some time, and until then, there is a need to detect such inconsistencies. Once we detect inconsistencies, then we could have two options: 1) restart the node or 2) Fix the inconsistencies on the fly. ``` The [Cassandra Jira](https://issues.apache.org/jira/browse/CASSANDRA-18758) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
