Memory Management in WordPress
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The document discusses strategies for managing memory usage in PHP, particularly within WordPress environments. It highlights the importance of monitoring memory consumption through various tools and advises on coding practices to prevent memory exhaustion errors. Recommendations include profiling techniques, optimizing database queries, and configuring memory limits effectively.
![add_action( 'shutdown', function() {
$line = json_encode( array(
'timestamp' => time(),
'request_uri' => $_SERVER['REQUEST_URI'],
'peak_memory' => memory_get_peak_usage(),
) );
file_put_contents( '/tmp/php-memory.log',
$line . PHP_EOL, FILE_APPEND | LOCK_EX );
});](https://image.slidesharecdn.com/wcsof-konstantin-kovshenin-memory-4-161022100918/85/Memory-Management-in-WordPress-52-320.jpg)
Memory Management in WordPress
- 1. Keep Your Memory Under Control Konstantin Kovshenin konstantin.blog
- 3. Fast
- 6. Memory Usage free top, htop, ...
- 7. free
- 8. free
- 9. top
- 10. top
- 11. PHP / WordPress
- 13. Zend Memory Manager OS Kernel foo.php $a = 5; malloc, mmap, ...
- 14. memory_get_usage() memory_get_peak_usage() Debug Bar, Query Monitor Memory Usage
- 15. $before = memory_get_usage(); // Do something $after = memory_get_usage(); echo $after - $before;
- 16. Environment loaded Init action Shutdown action 12.9 MB 14.1 MB 14.4 MB
- 17. 12.9 MB 14.1 MB 14.4 MB 12.9 MB 27.3 MB 28.6 MB Environment loaded Init action Shutdown action
- 18. Fatal error: Allowed memory size of 134217728 bytes exhausted
- 19. ... tried to allocate 8552 bytes in /path/to/wp-includes/wp-db.php on line 1775
- 20. ... tried to allocate 8552 bytes in /path/to/wp-includes/wp-db.php on line 1775 1775: while ( $row = mysqli_fetch_object( ...
- 21. ... tried to allocate 8552 bytes in /path/to/wp-includes/wp-db.php on line 1775 1775: while ( $row = mysqli_fetch_object( ...
- 22. Google...
- 25. Stop
- 30. OOM Killer
- 32. 1. Fine-tune the OOM
- 33. 1. Fine-tune the OOM 2. Add more Swap memory
- 34. 1. Fine-tune the OOM 2. Add more Swap memory 3. Figure things out
- 35. ... tried to allocate 8552 bytes in /path/to/wp-includes/wp-db.php on line 1775
- 37. Call Stack: 34032184 6. do_action() .../htdocs/wp-settings.php:393 34925000 7. call_user_func_array:{}() .../wp-includes/plugin.php:525 34925104 8. my_plugin_init() .../wp-includes/plugin.php:525 134139664 9. wpdb->query() .../wp-content/plugins/memory.php:25 134172496 10. mysqli_fetch_object() .../wp-includes/wp-db.php:1775
- 39. vim trace.xt
- 40. Why?
- 42. // Pretty bad $posts = get_posts( array( 'posts_per_page' => -1, // ... ) ); foreach ( $posts as $post ) { // ... }
- 43. // A little better $paged = 1; while ( $posts = get_posts( array( 'posts_per_page' => 100, 'paged' => $paged++, ) ) ) { foreach ( $posts as $post ) { // ... } }
- 44. // Good wp_suspend_cache_addition( true ); $paged = 1; while ( $posts = get_posts( array( 'posts_per_page' => 100, 'paged' => $paged++, ) ) ) { // foreach ... } wp_suspend_cache_addition( false );
- 47. ob_start()
- 48. // Not so good ob_start( 'ob_callback' ); // Much better ob_start( 'ob_callback', 1024*1024*2 ); function ob_callback( $content, $phase ) { // ... }
- 49. Context
- 51. Monitoring top, free cat /proc/meminfo cat /proc/pid/{status,maps}
- 52. add_action( 'shutdown', function() { $line = json_encode( array( 'timestamp' => time(), 'request_uri' => $_SERVER['REQUEST_URI'], 'peak_memory' => memory_get_peak_usage(), ) ); file_put_contents( '/tmp/php-memory.log', $line . PHP_EOL, FILE_APPEND | LOCK_EX ); });
- 54. Munin
- 55. 1. Choose the right context
- 56. 2. Profile with large datasets
- 57. 3. Keep consumption under control
- 59. Attributions: Success Kid (Sammy Griner): https://en.wikipedia.org/wiki/Success_Kid Ninja character: http://www.vecteezy.com/vector-art/88129-ninja-vector-set Blood spatter CC-Attr-ShareALike 4.0: http://www.freevector.com/splattered-blood-graphics-set User icons by FontAwesome, SIL OFL 1.1: http://fontawesome.io