[CASSANDRA-17186] Guardrail for number of partition keys on IN queries

• Type: New Feature
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.1-alpha1, 4.1
• Component/s: Feature/Guardrails
• Labels: AdventCalendar2021 lhf
• Epic Link: CEP-3: Guardrails
• Change Category: Operability
• Complexity: Low Hanging Fruit
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/7ea0a4aa410e9d0d252115607ac5c31d37784357

Test and Documentation Plan

Unit tests.

• Assignee: Krishna Vadali
• Reporter: Andres de la Peña

Authors

Krishna Vadali

Reviewers

Andres de la Peña, Berenguer Blasi

• Created: 06/Dec/21 12:35
• Updated: 02/Apr/23 12:29
• Resolved: 23/Feb/22 12:51

Description

Add a guardrail for limiting the number of partitions restricted with an IN clause in a SELECT query, for example:

# Guardrail to warn or abort when querying with an IN restriction selecting
# more partition keys than threshold.
# The two thresholds default to -1 to disable. 
partition_keys_in_select:
    warn_threshold: -1
    abort_threshold: -1

Additional information for newcomers:

• Add the configuration for the new guardrail on the number of partitions on IN queries in the guardrails section of cassandra.yaml.
• Add a getPartitionKeysInSelect method in GuardrailsConfig returning a Threshold.Config object
• Implement that method in GuardrailsOptions, which is the default yaml-based implementation of GuardrailsConfig
• Add a Threshold guardrail named partitionKeysInSelect in Guardrails, using the previously created config
• Define JMX-friendly getters and setters for the previously created config in GuardrailsMBean
• Implement the JMX-friendly getters and setters in Guardrails
• Now that we have the guardrail ready, it’s time to use it. We should search for a place to invoke the Guardrails.partitionKeysInSelect#guard method with the number of keys specified in select query. The SelectStatement#getSliceCommands methods look like good candidates for this.
• Finally, add some tests for the new guardrail. Given that the new guardrail is a Threshold, our new test should probably extend ThresholdTester.

Issue Links

• fixes: CASSANDRA-9454 Log WARN on Multi Partition IN clause Queries
• is related to: CASSANDRA-17187 Guardrail for SELECT IN terms and their cartesian product
• links to: PR trunk