[CASSANDRA-19341] Relation and Restriction hierarchies are too complex and error prone

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 5.1
• Component/s: CQL/Interpreter
• Change Category: Code Clarity
• Complexity: Normal
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/534da538d229a5b4fc1d9ef7cc8b37ead455191c

Test and Documentation Plan

The patch adds new tests for some of the new classes and relies on existing tests to validate the changes.

• Assignee: Benjamin Lerer
• Reporter: Benjamin Lerer

Authors

Benjamin Lerer

Reviewers

Berenguer Blasi, Caleb Rackliffe, Ekaterina Dimitrova

• Created: 30/Jan/24 10:59
• Updated: 07/May/24 13:47
• Resolved: 06/May/24 17:53

Description

The Relation and Restriction hierarchy have been designed when C* was only supporting a limited amount of operators and columns expressions (single column, multi-column and token expressions). Over time they have grown in complexity making the code harder to understand and modify and error prone. Their design is also resulting in unnecessary limitations that could be easily lifted, like the ability to accept different predicates on the same column.

Today adding a new operator requires the addition of a lot of glue code and surgical changes accross the CQL layer. Making patch for features such as CASSANDRA-18584 much complex than it should be.

The goal of this ticket is to simplify the Relation and Restriction hierarchies and modify operator class so that adding new operators requires only changes to the Operator class and ANTLR file.

Issue Links

• blocks: CASSANDRA-18584 CEP-29: NOT operator
• relates to: CASSANDRA-19620 Refactor ColumnCondition post CASSANDRA-19341
• links to: GitHub Pull Request #3095