opcacherelated

Opcache-related refers to topics surrounding OPcache, a PHP extension that caches precompiled PHP opcode to speed execution. OPcache stores compiled bytecode in shared memory, eliminating the need to recompile scripts on each request. This reduces CPU usage and response times in web applications and in PHP command-line workflows. OPcache originated with Zend Technologies and is bundled with PHP, aiding faster request handling in production deployments using Apache with mod_php, Nginx with PHP-FPM, or the PHP CLI.

OPcache works by compiling PHP scripts to opcodes once and serving cached opcodes from memory on subsequent requests. It detects changes to source files and invalidates stale entries. Features include configurable memory usage, interned strings, and an optional file-based cache. In PHP 8, OPcache also includes optional Just-In-Time compilation to accelerate certain execution paths.

Configuration is controlled chiefly via php.ini directives. Common options include opcache.enable, opcache.enable_cli, opcache.memory_consumption, opcache.interned_strings_buffer, opcache.max_accelerated_files, opcache.validate_timestamps, opcache.revalidate_freq, opcache.file_cache, and opcache.preload. Administrators can inspect status via opcache.get_status() or phpinfo().

In production, tuning emphasizes sufficient memory, sensible revalidation settings, and preloading for hot paths; in development the cache is often disabled to reflect code changes immediately.

See also: PHP, OPcache, Zend Opcache.