{
  "id": 19592750,
  "title": "How to Detect and Fix PHP Memory Leaks",
  "url": "https://urgent.news/2026/11/12/how-to-detect-and-fix-php-memory-leaks",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-11-12T03:24:24.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/devtalk94/how-to-detect-and-fix-php-memory-leaks-4e14"
  },
  "original_language": "en",
  "account": "Detecting and fixing PHP memory leaks can be a challenging task, but understanding the common causes and implementing the right strategies can help maintain optimal performance. PHP processes typically release memory when a request ends, but leaks can occur in long-running processes like queue workers, daemons, and application servers. The main symptom is a gradual increase in memory usage until the system either runs out of memory or the process is terminated. This article outlines a step-by-step approach to confirm if a memory leak exists, identify the primary causes, and find solutions.\n\nTo test for memory leaks, create a function that prints memory usage at regular intervals during repeated work. If the memory usage plateaus, there is no leak. If it continues to rise steadily, a leak is likely present. The following PHP function demonstrates this approach:\n\n```\nfunction report(string $label): void {\nprintf('%s: %.1f MB (peak %.1f MB)\\n',\n$label,\nmemory_get_usage() / 1048576,\nmemory_get_peak_usage() / 1048576);\n}\n```\n\nNext, run the same task multiple times and monitor memory usage. If it increases linearly, a leak is probable. PHP offers three useful functions for memory measurement:\n\n1. memory_get_usage(): current allocation\n2. memory_get_usage(true): system reservation\n3. memory_get_peak_usage(): highest memory usage\n\nWith PHP 8.2, memory_reset_peak_usage() allows you to measure memory usage in smaller increments. In the provided example, a 50 MB string freed after a single request still left a peak value of 50.4 MB. After a reset, the peak usage dropped to 0.4 MB.\n\nThe first cause of memory leaks often stems from static arrays, singletons, or globals that accumulate data over time. By simulating 50,000 units of work and storing a 1 KB payload in a static cache, you can observe significant memory growth:\n\n```\nafter 10000: 12.9 MB\nafter 50000: 62.5 MB\n```\n\nHowever, a bounded cache with a maximum size can prevent this issue. Alternatively, avoid caching when the data is inexpensive to reload. Another solution involves using WeakMap to tie cached data to the object it belongs to, allowing PHP to automatically remove weakly referenced entries:\n\n```\n$map = new WeakMap();\n$user = new stdClass();\n$map[$user] = [expensive_data];\necho count($map); // 1\nunset($user);\necho count($map); // 0\n```\n\nIn Laravel, avoid using singletons, static properties on services, or traits with static state, as these can lead to memory leaks when used in Octane or queue:work environments.\n\nThe second primary cause of memory leaks is circular references. PHP's garbage collector (GC) typically frees objects once they are no longer referenced, but cycles prevent this. To mitigate this, enable the GC and call gc_collect_cycles() periodically, especially when dealing with large object graphs or parsed documents. Breaking cycles by manually releasing references can also help:\n\n```\nclass Report {\npublic $cb;\npublic $data;\npublic function __construct(bool $static) {\n$this->data = str_repeat('x', 100000);\n$this->cb = $static ? static fn() => 1 : fn() => $this->data;\n}\n}\n```\n\nIn this case, circular references were freed after garbage collection, but disabling the collector made the issue worse.\n\nBy following these steps and implementing the suggested fixes, you can effectively detect and address PHP memory leaks, ensuring optimal performance in your applications.",
  "summary": "Last updated: 5 November 2026. See the update log at the end. In a normal PHP-FPM request, a memory leak mostly does not exist: PHP frees everything when the request ends. The leaks people actually hit happen in processes that stay alive: queue workers, daemons, long import scripts, and application servers like Laravel Octane. The symptom is always the same. Memory climbs a little with every job…",
  "key_points": [
    "PHP memory leaks occur in long-running processes like queue workers and daemons",
    "Detect leaks by monitoring memory usage at regular intervals during repeated work",
    "Fix leaks by avoiding static caches, circular references, and using WeakMap"
  ],
  "editors_take": "Managing long-running processes requires moving beyond standard request cycles to address the risks posed by static state, circular references, and unmanaged caches in modern PHP environments.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}