Phase 3-3: Adaptive Cache TTLs

[ashleyshaw]

Overview

Replace fixed TTL caching with intelligent, data-pattern-aware TTL strategies.

Objective: Increase cache hit rates beyond Phase 2C's 55% by using adaptive TTLs that match data update patterns for different GitHub entities.

Context

Phase 2C implemented fixed 5-minute TTL caching across all queries. However, different data has different update frequencies:

• Labels and milestones: rarely change (could use 1-hour TTL)
• PR status: frequently changes (needs 1-minute TTL)
• Issue assignments: moderately frequent changes (5-10 minute TTL)

Fixed TTLs compromise between staleness and cache hit rate. Adaptive TTLs can optimize both.

Success Metrics

• Overall cache hit rate improvement from 55% → 65-75%
• Reduced API calls by additional 5-10% vs Phase 2C
• Zero cache staleness incidents in staging validation
• Configurable per-data-type policies
• 100% test coverage for TTL policy logic

Deliverables

• Adaptive cache manager (scripts/automation/includes/adaptive-cache.js)
• TTL policies by data type (labels, PRs, issues, assignees, milestones)
• Cache invalidation triggers (webhook-based invalidation)
• Metrics tracking (hit rate, staleness events, TTL distribution)
• Configuration schema for TTL policies

Acceptance Criteria

• Adaptive cache manager implemented
• Per-data-type TTL policies defined and configurable
• Cache hit rate improved to 65-75% (from 55%)
• Webhook invalidation patterns tested
• Zero staleness incidents in staging (7-day validation)
• Performance regression detection in Phase 3-2 validates improvements
• Configuration documentation complete

Dependencies

• Phase 2C response cache exists
• Webhook integration research (Phase 3-5) informs invalidation strategy
• Phase 3-2 continuous benchmarking for validation

Estimated Effort

6-8 business days

Links

• Phase 3 Planning: PHASE_3_PLANNING.md
• Outstanding Gaps: OUTSTANDING_GAPS.md``
• Phase 2C Cache Implementation: scripts/automation/includes/response-cache.js

---

Phase 3 planning issue for secondary automation script optimization project.

[linear-code]

LS-2998

[github-actions]

⚠️ This issue does not follow a required issue template.

Missing required section(s): Definition of Ready (DoR), Definition of Done (DoD)

The issue will remain open and flagged until the body is corrected.
Please update the issue with one of the official templates:

• https://github.com/lightspeedwp/.github/issues/new/choose

If this was opened by automation, update the automation to preserve the template sections before creating the issue.