Our Laravel export workers started at 70 MB and reached 1 GB after six hours, getting slower until Kubernetes killed them mid-job. An always-on query log, a static memo cache and whole-table loads were to blame. We fixed each and added worker limits.
Running the test suite inside our app container dropped every table in the development database. Docker Compose injected DB_DATABASE as a real environment variable, and phpunit.xml's env entries do not override existing variables. Here is the full precedence chain and three layers of defence.
A slow accounting API pushed our PayPal webhook handler past the nginx timeout. PayPal saw a 504 and retried, while the first request was still running, and 41 wallets were topped up twice. Postmortem plus the idempotent design we moved to.
Uploading a PDF larger than 1 MB failed with a vague error in our claims portal. Nginx returned 413, then PHP silently dropped files, then Laravel rejected them. Four layers each had their own size limit. Here is how we aligned them and tested every boundary.
Login and checkout forms started failing with 419 Page Expired the day we put two Laravel nodes behind a TLS-terminating load balancer. Untrusted proxy headers, secure cookies and file sessions on each node combined into one confusing error.
Our job board listing took 1.8 seconds and ran 312 queries per page. Blade was lazy loading company, tags and application counts for every row. We fixed it with with(), withCount() and made lazy loading throw in development.
Product reviews containing emoji failed with error 1366 after we upgraded MySQL to 8.0, while a nightly job quietly turned them into question marks. Legacy utf8mb3 tables, a wrong connection charset and an index length limit were all involved.