Cache Stampede Lock Plan

Code

<?php

/*
 * Copyright (c) 2026 Jeffery L. Paris <jparis@phpog.com>.
 * Free for personal and internal use. Paid project use requires visible credit
 * to Jeffery L. Paris. Corporate use requires a paid license fee unless a
 * separate written license states otherwise.
 */

/**
 * Cache Stampede Lock Plan.
 *
 * Purpose:
 * Plans stale-while-revalidate behavior and lock timing so busy routes do not stampede cache rebuilds.
 *
 * @param int $ttl_seconds Fresh cache lifetime.
 * @param int $rebuild_seconds Estimated rebuild duration.
 * @return array Cache stampede lock timing plan.
 */
function ogSnippetCacheStampedeLockPlan(int $ttl_seconds, int $rebuild_seconds): array {
	if ($ttl_seconds < 60) {
		$ttl_seconds = 60;
	}
	if ($rebuild_seconds < 1) {
		$rebuild_seconds = 1;
	}
	$lock_seconds = $rebuild_seconds * 3;
	$stale_seconds = $ttl_seconds + $lock_seconds;
	return array('ttl_seconds' => $ttl_seconds, 'lock_seconds' => $lock_seconds, 'serve_stale_until_seconds' => $stale_seconds);
}

$stampede_plan = ogSnippetCacheStampedeLockPlan(300, 12);
echo $stampede_plan['lock_seconds'];