OPcache Preloading¶

OPcache preloading, introduced in version 7.4, allows loading PHP files into shared memory at PHP-FPM startup so they are permanently available to all worker processes without any parsing overhead on each request.

A preload script is specified with opcache.preload in php.ini. All files required or compiled in that script are cached for the lifetime of the PHP-FPM master process. Changes to preloaded files require a PHP-FPM restart to take effect.

Preloading is most effective for framework core files, base classes, and heavily-used libraries.

<?php

    // preload.php  —  referenced in php.ini:
    // opcache.preload = /var/www/preload.php
    // opcache.preload_user = www-data

    // Preload all PHP files from the framework kernel
    $dir  = new RecursiveDirectoryIterator('/var/www/vendor/symfony/http-kernel');
    $iter = new RecursiveIteratorIterator($dir);

    foreach ($iter as $file) {
        if ($file->getExtension() === 'php') {
            opcache_compile_file($file->getPathname());
        }
}

?>

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OPcache Preloading¶

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