Use cursor pagination for backfill query to improve performance.

[ggreer]

Summary by CodeRabbit

• Chores
  • Improved grant data processing performance through more efficient batching of database operations.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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Walkthrough

The backfillGrantExpansionColumn function has been refactored to implement cursor-based pagination using row IDs instead of rescanning from the beginning. A lastID variable tracks pagination progress, the query filters rows with g.id > lastID, and batches are limited to 1000 rows.

Changes

Cohort / File(s)	Summary
Pagination Optimization pkg/dotc1z/grants.go	Refactored backfillGrantExpansionColumn to use cursor-based pagination via ID tracking. Added lastID variable to filter and paginate through rows incrementally, reducing redundant scans and improving efficiency when processing large datasets.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 With cursor in paw, this rabbit hops fast,
No more scanning the whole dataset past!
By ID we now bound, through records we race,
Pagination optimized—a much speedier place! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Use cursor pagination for backfill query to improve performance' directly and accurately describes the main change: replacing offset-based pagination with cursor-based pagination in the backfillGrantExpansionColumn function.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch ggreer/backfill-faster

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