[CASSANDRA-18940] SAI post-filtering reads don't update local table latency metrics

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 5.0-rc1, 5.0, 5.1
• Component/s: Feature/2i Index, Feature/SAI, Observability/Metrics
• Epic Link: Storage Attached Indexes (Phase 3)
• Bug Category: Correctness
• Severity: Low
• Complexity: Normal
• Discovered By: User Report
• Platform: All
• Since Version: 5.0-alpha1

Source Control Link

https://github.com/apache/cassandra/commit/1d7bae3697b97e64de2c2b958427ef86a1b17731

Test and Documentation Plan

added a tiny addition to QueryMetricsTest that makes sure latencies are being recorded

• Assignee: Caleb Rackliffe
• Reporter: Caleb Rackliffe

Authors

Caleb Rackliffe

Reviewers

Mike Adamson

• Created: 18/Oct/23 21:39
• Updated: 18/Jul/24 21:11
• Resolved: 26/Feb/24 21:35

Description

Once an SAI index finds matches (primary keys), it reads the associated rows and post-filters them to incorporate partial writes, tombstones, etc. However, those reads are not currently updating the local table latency metrics. It should be simple enough to attach a metrics recording transformation to the iterator produced by querying local storage.

Issue Links

• links to: GitHub Pull Request #3122
• links to: GitHub Pull Request #3138