perf: bound unbounded findMany queries (#1206)

[LucasSantana-Dev]

Closes part of #1206 by bounding two critical unbounded Prisma queries in hot paths.

Summary

• Birthday scheduler (packages/bot/src/utils/general/birthdayScheduler.ts):
  Paginate guildSettings.findMany() in role reconciliation with take:500
  cursor-based pagination. Prevents full-table scans on large deployments when
  reconciling guilds without birthday role matches.

• Feedback service (packages/bot/src/services/musicRecommendation/feedbackService.ts):
  Cap userArtistPreference.findMany() with take:5000 to protect against
  power-user preference sprawl in the autoplay scoring path.

Implementation details

• Birthday scheduler pagination uses Prisma cursor + take + skip pattern with
  guildId ordering to safely traverse large result sets in 500-guild chunks.
• Feedback service bounds respect typical user behavior (<100 prefs) while protecting
  against edge cases.
• Behavior is preserved: birthday scheduler still reconciles all guilds over time
  (pagination is transparent); feedback scoring includes all user prefs up to 5000.

Tests added

• Birthday scheduler: pagination with multiple pages and early-stop scenarios
• Feedback service: bounds enforcement for preferred and blocked artist queries
• All existing tests still pass

Follow-ups

• Database indexes on (birthdayRoleId) and (discordUserId, guildId, preference)
  recommended for further optimization (out of scope for this PR).

---

Summary by cubic

Bound two unbounded Prisma queries in hot paths to prevent full-table scans and reduce latency on large deployments. Addresses part of Linear #1206.

• Refactors
  • Birthday scheduler: paginate guildSettings.findMany with cursor-based 500-row pages ordered by guildId to reconcile roles for guilds without matches without scanning the table.
  • Feedback service: cap userArtistPreference.findMany with take: 5000 for preferred/blocked artist lookups in autoplay scoring.

^{Written for commit 3f33b26. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes

  • Improved stability of music recommendation service by implementing query limits
  • Enhanced birthday scheduler efficiency with optimized batch processing

• Tests

  • Added test coverage for query optimization improvements

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Project	Deployment	Actions	Updated (UTC)
lucky	Ready	Preview, Comment	Jun 4, 2026 9:29pm

[greptile-apps]

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[coderabbitai]

📝 Walkthrough

Walkthrough

This PR adds result limits to two database query paths in the bot services to prevent unbounded record retrieval. The music recommendation service caps artist preference lookups at 5000 records per query, and the birthday scheduler replaces a single unbounded guild settings query with paginated 500-record batches.

Changes

Database Query Result Bounding

Layer / File(s)	Summary
Artist preference query bounding packages/bot/src/services/musicRecommendation/feedbackService.ts, packages/bot/src/services/musicRecommendation/feedbackService.spec.ts	getArtistKeysFromDb adds a take: 5000 limit to Prisma findMany queries for preferred and blocked artist preferences. Tests mock large result sets and verify the take option is applied correctly.
Guild settings pagination packages/bot/src/utils/general/birthdayScheduler.ts, packages/bot/src/utils/general/birthdayScheduler.spec.ts	Imports are refactored to multiline form. reconcileGuildsWithoutMatches replaces unbounded guildSettings.findMany with cursor-based pagination using PAGE_SIZE and take: 500. Test helpers are reformatted and two new test cases verify pagination behavior across multiple batches and early termination when a page is smaller than the batch limit.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• LucasSantana-Dev/Lucky#1012: Refactors the same artist key getters (getPreferredArtistKeys/getBlockedArtistKeys) that are now bounded with take: 5000.
• LucasSantana-Dev/Lucky#572: Modifies the artist preference handling path where this PR adds the take: 5000 cap to the underlying database queries.

Suggested labels

bot, enhancement, size/m

🚥 Pre-merge checks | ✅ 4 | ❌ 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 (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'perf: bound unbounded findMany queries' accurately and concisely describes the main objective of the PR—adding bounds to unbounded Prisma queries to improve performance.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch perf/bound-unbounded-queries

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[github-actions]

Failed to generate code suggestions for PR

[cubic-dev-ai]

No issues found across 4 files

<sub>Auto-approved: This PR adds safe query limits (pagination and take) to two unbounded Prisma queries in non-critical performance paths, preserving existing behavior and reducing risk of full-table scans without altering business logic.

Re-trigger cubic</sub>

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[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
95.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud