Topics
Grouped by what broke, not by which tool it happened in.
01
Caching
Expiry, stampedes, and what the cache was doing while it lied.
202
Databases
Storage engines holding state: bloat, locks, pool saturation.
4- p50 is fine. p99 is 6 seconds. Every endpoint, not just the slow one.postgres · connection-pool · multi-tenantmedium
- No deploy. No traffic change. Queries just keep getting slower, day over day.postgres · autovacuum · bloatmedium
- Support is full of tickets. Some customers were charged twice, and some were charged once but have no order.idempotency · payments · retries · distributed-systemshard
- 40 rows in 1ms. 6 million rows in 9 seconds, with a sequential scan — on a table that has an index on user_id.query-planner · indexes · sequential-scan · mvcchard
03
Runtime
The process itself: memory, GC, and the pauses inside it.
3- 100,000 requests in. The counter says 97,832 — every run, a different shortfall.go · concurrency · race-condition · atomics · runtimemedium
- CPU graph says 45%. p99 latency says otherwise.jvm · garbage-collection · latencyhard
- 5,000 req/sec. App server CPU at 100%, Postgres under 20%. Latency goes from 5ms to 400ms.go · connection-pool · concurrency · pprofmedium
04
Platform
Orchestration, probes, and the failure of a control plane.
1