Long Running PHP by Kamil Szymanski
0 likes77 views
The document discusses issues with PHP scripts slowing down, using excessive RAM, or crashing unexpectedly. It explains that these issues can be caused by the PHP garbage collector when too many objects are created. The garbage collector has a limit on the number of root objects it can track, and if this limit is exceeded, it may not clean up memory efficiently. Disabling the garbage collector may help avoid these performance problems, but could also lead to memory leaks if circular references are created but not cleaned up. Further tuning of garbage collection settings or using alternative languages like Java may help address long-running script issues.
Long Running PHP by Kamil Szymanski
- 2. Did you go through that already? ❏ My script slows down with a time ❏ My script consumes extreme amount of RAM ❏ My script dies from time to time with no reason
- 3. How to fix it?
- 4. Use Java
- 5. Use Java
- 7. Get familiar with Garbage Collector
- 8. The Composer case Generally if you create many many objects, you pretty much want to always disable GC. This is because PHP has a hard-coded limit (compile-time) of root objects that it can track in its GC implementation (I believe it's set to 10000 by default). If you get close to this limit, GC kicks in. If it cannot clean-up, it will still keep trying in frequent intervals. If you go above the limit, any new root objects are not tracked anymore, and cannot be cleaned-up whether GC is enabled, or not. This might also be why the memory consumption for bigger projects does not vary. If GC is enabled, it's just not working anymore even if there is potentially something to clean-up. For smaller projects, you might see a memory difference. https://github.com/composer/composer/pull/3482#issuecomment-65199153
- 9. So why is my script slowing down? When the garbage collector is turned on, the cycle-finding algorithm as described above is executed whenever the root buffer runs full. The root buffer has a fixed size of 10,000 possible roots (although you can alter this by changing the GC_ROOT_BUFFER_MAX_ENTRIES constant in Zend/zend_gc.c in the PHP source code, and re-compiling PHP). When the garbage collector is turned off, the cycle-finding algorithm will never run. However, possible roots will always be recorded in the root buffer, no matter whether the garbage collection mechanism has been activated with this configuration setting. If the root buffer becomes full with possible roots while the garbage collection mechanism is turned off, further possible roots will simply not be recorded. Those possible roots that are not recorded will never be analyzed by the algorithm. If they were part of a circular reference cycle, they would never be cleaned up and would create a memory leak. From http://php.net/manual/en/features.gc.collecting-cycles.php https://www.reddit.com/r/lolphp/comments/2o1w4a/php_garbage_collector_at_its_finest/
- 10. The Garbage Collector at it’s best
- 11. The Garbage Collector at it’s best
- 12. The Garbage Collector at it’s best
- 13. Solution?
- 14. Thank you