php system_error ai_generated true

Warning: session_start(): Session GC failed in /var/www/app/src/Session/SessionManager.php:35

ID: php/session-gc-probability-high

Also available as: JSON · Markdown · 中文
80%Fix Rate
86%Confidence
1Evidence
2024-01-10First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
PHP 7.4 active — — —
PHP 8.0 active — — —
PHP 8.1 active — — —
PHP 8.2 active — — —
PHP 8.3 active — — —

Root Cause

PHP's session garbage collection (GC) fails due to permission issues on the session save path, disk full, or a misconfigured GC probability that triggers too frequently.

generic

中文

PHP 的会话垃圾回收（GC）失败，原因是会话保存路径的权限问题、磁盘已满或 GC 概率配置不当导致触发过于频繁。

Official Documentation

https://www.php.net/manual/en/session.configuration.php#ini.session.gc-probability

Workarounds

  1. 90% success Fix permissions on the session save path: run 'sudo chmod 733 /var/lib/php/sessions' and 'sudo chown www-data:www-data /var/lib/php/sessions' (adjust user/group as needed). 
    Fix permissions on the session save path: run 'sudo chmod 733 /var/lib/php/sessions' and 'sudo chown www-data:www-data /var/lib/php/sessions' (adjust user/group as needed).
  2. 85% success Check disk space with 'df -h' and free up space if necessary. If using tmpfs for sessions, ensure enough memory is allocated. 
    Check disk space with 'df -h' and free up space if necessary. If using tmpfs for sessions, ensure enough memory is allocated.
  3. 75% success Reduce GC probability by setting session.gc_probability=1 and session.gc_divisor=1000 in php.ini to trigger GC once every 1000 requests, reducing load. 
    Reduce GC probability by setting session.gc_probability=1 and session.gc_divisor=1000 in php.ini to trigger GC once every 1000 requests, reducing load.

中文步骤

  1. Fix permissions on the session save path: run 'sudo chmod 733 /var/lib/php/sessions' and 'sudo chown www-data:www-data /var/lib/php/sessions' (adjust user/group as needed).
  2. Check disk space with 'df -h' and free up space if necessary. If using tmpfs for sessions, ensure enough memory is allocated.
  3. Reduce GC probability by setting session.gc_probability=1 and session.gc_divisor=1000 in php.ini to trigger GC once every 1000 requests, reducing load.

Dead Ends

Common approaches that don't work:

  1. 80% fail

    Setting session.gc_probability=0 disables GC entirely, which prevents the warning but leads to session file accumulation and potential disk space issues.

  2. 65% fail

    Increasing session.gc_divisor to 1000 reduces GC frequency but does not fix underlying permission or disk problems; the warning may still appear sporadically.