perf(db): query fingerprint metrics and home page query optimization#577
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…me page queries - Add fingerprint label to db_query_duration_seconds histogram for identifying slow query shapes - Add skipCount option to ContrailQueryService.find() to avoid unnecessary COUNT(*) scans - Replace ORDER BY RANDOM() in getHomePageFeaturedGroups with two-query ID-then-fetch pattern Addresses consistent 500ms p99 SELECT query duration in production.
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tompscanlan
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Apr 23, 2026
* revert: remove unreleased features from main, align with prod (v1.5.1) Reverts unreleased features to bring main back in sync with production: - #577 perf(db): query fingerprint + home page optimization - #576 feat: unified AttendanceService - #574 feat(contrail): integrate Contrail appview Hotfix changes (v1.5.1) are retained — they exist in the baseline. All work is preserved on its respective feature branch: - feature/contrail-integration - feature/attendance-service - feature/db-query-performance - feature/contrail-rsvp Direction shift: adopting Contrail/atmo as the new stack rather than integrating Contrail into the OpenMeet API. * fix(test): use future dates in edge-cases spec to avoid past-event guard The hotfix (v1.5.1) added a past-event RSVP guard that rejects RSVPs to events with past start dates. The edge-cases spec used 2024 dates, hitting the guard before reaching the race condition logic under test.
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Summary
db_query_duration_secondsPrometheus histogram — enables identifying which specific SQL query shapes are slow (fingerprint already computed, just threaded to metric label)skipCountoption toContrailQueryService.find()— guest home page skips the redundant COUNT(*) full table scan since it only random-samples 4 events from 50ORDER BY RANDOM()ingetHomePageFeaturedGroupswith a two-query ID-then-fetch pattern — avoids full table sort with JOINsAddresses consistent 500ms p99 SELECT query duration in production (confirmed via Prometheus: p95=432ms, p99=486ms on SELECT operations).
Relates to: om-otp8, om-kcmj
Test plan
database-metrics.service.spec.ts— 4 new tests for fingerprint labelcontrail-query.service.spec.ts— 3 new tests for skipCount optionevent-query.service.spec.ts— 1 new test for skipCount passthroughgroup.service.spec.ts— 2 new tests for two-query featured groups patterndb_query_duration_seconds