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  1. Cassandra
  2. CASSANDRA-6659

Allow "intercepting" query by user provided custom classes



    • Improvement
    • Status: Resolved
    • Low
    • Resolution: Fixed
    • 2.0.7
    • None
    • None


      The idea for this ticket is to abstract the main execution methods of QueryProcessor into an interface, something like:

      public interface QueryHandler
          public ResultSet process(String query, QueryState state, QueryOptions options);
          public ResultMessage.Prepared prepare(String query, QueryState state);
          public ResultSet processPrepared(CQLStatement statement, QueryState state, QueryOptions options);
          public ResultSet processBatch(BatchStatement statement, QueryState state, BatchQueryOptions options);

      and to allow users to provide a specific class of their own (implementing said interface) to which the native protocol would handoff queries to (so by default queries would go to QueryProcessor, but you would have a way to use a custom class instead).

      A typical use case for that could be to allow some form of custom logging of incoming queries and/or of their results. But this could probably also have some application for testing as one could have a handler that completely bypass QueryProcessor if you want, say, do perf regression tests for a given driver (and don't want to actually execute the query as you're perf testing the driver, not C*) without needing to patch the sources. Those being just examples, the mechanism is generic enough to allow for other ideas.

      Most importantly, it requires very little code in C*. As for how users would register their "handler", it can be as simple as a startup flag indicating the class to use, or a yaml setting, or both.


        1. 6659.txt
          24 kB
          Sylvain Lebresne



            slebresne Sylvain Lebresne
            slebresne Sylvain Lebresne
            Sylvain Lebresne
            Sam Tunnicliffe
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