[BUG] Sparse index does not sort offset id

[Sicheng-Pan]

Description of changes

Summarize the changes made by this PR.

• Improvements & Bug fixes
  • RecordMeasure should sort by offset id as well to break ties deterministically
  • SparseIndexKnn output should sort by offset id to maintain overall order
• New functionality
  • N/A

Test plan

How are these changes tested?

• Tests pass locally with pytest for python, yarn test for js, cargo test for rust

Migration plan

Are there any migrations, or any forwards/backwards compatibility changes needed in order to make sure this change deploys reliably?

Observability plan

What is the plan to instrument and monitor this change?

Documentation Changes

Are all docstrings for user-facing APIs updated if required? Do we need to make documentation changes in the docs section?

[Sicheng-Pan]

• [BUG] Sparse index does not sort offset id #5849 👈 (View in Graphite)
• main

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[github-actions]

Reviewer Checklist

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Testing, Bugs, Errors, Logs, Documentation

• Can you think of any use case in which the code does not behave as intended? Have they been tested?
• Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• If appropriate, are there adequate property based tests?
• If appropriate, are there adequate unit tests?
• Should any logging, debugging, tracing information be added or removed?
• Are error messages user-friendly?
• Have all documentation changes needed been made?
• Have all non-obvious changes been commented?

System Compatibility

• Are there any potential impacts on other parts of the system or backward compatibility?
• Does this change intersect with any items on our roadmap, and if so, is there a plan for fitting them together?

Quality

• Is this code of a unexpectedly high quality (Readability, Modularity, Intuitiveness)

[propel-code-bot]

Deterministic ordering for sparse-KNN results via tie-break on offset_id

Small fix to guarantee deterministic ordering when multiple sparse-KNN matches share the same distance. The PR augments the Ord implementation of RecordMeasure to compare offset_id as a secondary key and explicitly sorts the result vector returned by SparseIndexKnn::run() before it is consumed by downstream merge logic.

Key Changes

• Updated RecordMeasure::cmp() in rust/types/src/execution/operator.rs to call then_with(|| self.offset_id.cmp(&other.offset_id)) after measure.total_cmp
• Refactored rust/worker/src/execution/operators/sparse_index_knn.rs to collect wand results into Vec<RecordMeasure> and call records.sort_unstable() before wrapping in SparseIndexKnnOutput

Affected Areas

• RecordMeasure ordering semantics
• SparseIndexKnn operator output
• Any downstream logic that relies on sorted KNN results (e.g., KnnMerge, ranking)

This summary was automatically generated by @propel-code-bot