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  1. Cassandra
  2. CASSANDRA-15644

Schema/Query analyzer

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Details

    • New Feature
    • Status: Open
    • Normal
    • Resolution: Unresolved
    • 4.x
    • CQL/Syntax, Legacy/Tools
    • None
    • Operability
    • Challenging
    • All
    • None

    Description

      This proposal is to build schema/cql analyser which can help users to analyze their queries before it is too late.
       
      User may create stability issues by

      • Running expensive queries against cluster like , SELECT * or query without where clause or IN clause with many values etc.
      • Creating not so optimal schemas
      • Leaving scope for data loss or schema with performance issue (keyspace with durable writes set to false or table with many secondary indexes etc...).
         
        Most of the times these Dos & Don'ts go into some knowledge base/documentation as best practices. Having rules for best practices (which user can execute against statements) can help to avoid bad schema/queries getting executed in cluster. The main idea is to enable the users to take corrective actions, by
        1) Allowing a user to validate a DDL/DML statements before it is applied/executed.
        2) Allowing a user to validate existing schema/queries.
         
        Imo, a validation result should:
        1. Have severity
        2. Tell where it hurts like instance/replica set/cluster.
        3. Tell if it causes data loss.
        4. Tell the strategy to recover.
         
        Few approaches I can think of:
        1. Write validation rules at server side + have a new type of statement to run validations (something like MySQL's EXPLAIN) and return validation results/errors.
        2. Keep validation rules in sidecar + expose a service to run validations. In this case user can submit his statements to this API and get validation results.
        3. Expose a UI in sidecar which accepts statements and run validations. Validation rules can be with UI or UI can make either of above options.
         
        Open for any other approach.
         

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            n.v.harikrishna n.v.harikrishna
            n.v.harikrishna n.v.harikrishna
            n.v.harikrishna
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              Created:
              Updated: