Resource limits enforced on workers

A queue worker with no memory limit can consume all available host memory during a burst, taking down the database, Redis, and web server on the same host. CWE-400 (uncontrolled resource consumption) applies directly. The connection pool problem is multiplicative: 5 replicas with a default pg connection pool of 10 connections each create 50 connections — fine for one replica, catastrophic for five on a database with a max_connections of 25. ISO 25010 performance-efficiency.resource-utilization requires that resource consumption is bounded and predictable.

Add memory limits at the container level and set explicit connection pool sizes. In docker-compose.yml:

services:
  email-worker:
    mem_limit: 512m
    environment:
      - DATABASE_POOL_SIZE=5  # 5 per instance × replicas

And in the worker startup command:

node --max-old-space-size=400 dist/worker.js

Calculate pool size as: floor(max_connections / expected_replicas). At least 2 of 3 resource limits — memory, DB connection pool, Redis connection pool — must be explicitly configured.