dev.to/smtahosin/php-dies-after-every-request-how-the-zend-engine-actually-runs-your-code-2843 PHP Dies After Every Request. How the Zend Engine Actually Runs Your Code.
PHP's shared-nothing model gives each request an isolated heap that the Zend Engine clears afterward, preventing state leaks and containing crashes to one worker. The article traces compilation, OPcache bytecode caching, compact zvals, copy-on-write arrays, and PHP-FPM's master-worker pool.
