Cassandra easy
Cassandra Query Language (CQL) looks similar to SQL. What is a fundamental SQL feature that CQL does NOT support to ensure distributed performance?
- A The `SELECT` statement for retrieving data from a single table.
- B The `WHERE` clause for filtering results by a primary key.
- C Cross-table `JOIN` operations, as they are too computationally expensive in a distributed architecture.
- D The `INSERT` statement for adding new records.
Answer: C. Cross-table `JOIN` operations, as they are too computationally expensive in a distributed architecture.
Cassandra is a distributed non-relational database. Joining data across distributed nodes would require massive network 'chattiness' and 'shuffling', which kills performance. Cassandra forces 'Denormalization' (storing all data needed for a query in a single table).
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