Changeset 18659

Timestamp:

09/09/2011 07:59:44 PM (13 years ago)

Author:

ryan

Message:

Improve cron locking. Avoid multiple cron processes looping over the same events. fixes #17462

Location:

trunk

Files:

• wp-cron.php (modified) (2 diffs)
• wp-includes/cache.php (modified) (2 diffs)
• wp-includes/cron.php (modified) (3 diffs)
• wp-includes/default-constants.php (modified) (1 diff)

trunk/wp-cron.php

@@ -27 +27 @@
 }
 
+// Uncached doing_cron transient fetch
+function _get_cron_lock() {
+    global $_wp_using_ext_object_cache, $wpdb;
+
+    $value = 0;
+    if ( $_wp_using_ext_object_cache ) {
+        // Skip local cache and force refetch of doing_cron transient in case
+        // another processs updated the cache
+        $value = wp_cache_get( 'doing_cron', 'transient', true );
+    } else {
+        $row = $wpdb->get_row( $wpdb->prepare( "SELECT option_value FROM $wpdb->options WHERE option_name = %s LIMIT 1", '_transient_doing_cron' ) );
+        if ( is_object( $row ) )
+            $value = $row->option_value;
+    }
+
+    return $value;
+}
+
 if ( false === $crons = _get_cron_array() )
     die();
@@ -36 +54 @@
     die();
 
-foreach ($crons as $timestamp => $cronhooks) {
+$doing_cron_transient = get_transient( 'doing_cron');
+
+// Use global $doing_wp_cron lock otherwise use the GET lock. If no lock, trying grabbing a new lock.
+if ( empty( $doing_wp_cron ) ) {
+    if ( empty( $_GET[ 'doing_wp_cron' ] ) ) {
+        // Called from external script/job. Try setting a lock.
+        if ( $doing_cron_transient && ( $doing_cron_transient + WP_CRON_LOCK_TIMEOUT > $local_time ) )
+            return;
+        $doing_cron_transient = $doing_wp_cron = time();
+        set_transient( 'doing_cron', $doing_wp_cron );
+    } else {
+        $doing_wp_cron = $_GET[ 'doing_wp_cron' ];
+    }
+}
+
+// Check lock
+if ( $doing_cron_transient != $doing_wp_cron )
+    return;
+
+foreach ( $crons as $timestamp => $cronhooks ) {
     if ( $timestamp > $local_time )
         break;
 
-    foreach ($cronhooks as $hook => $keys) {
+    foreach ( $cronhooks as $hook => $keys ) {
 
-        foreach ($keys as $k => $v) {
+        foreach ( $keys as $k => $v ) {
 
             $schedule = $v['schedule'];
 
-            if ($schedule != false) {
+            if ( $schedule != false ) {
                 $new_args = array($timestamp, $schedule, $hook, $v['args']);
                 call_user_func_array('wp_reschedule_event', $new_args);
             }
 
-            wp_unschedule_event($timestamp, $hook, $v['args']);
+            wp_unschedule_event( $timestamp, $hook, $v['args'] );
 
-            do_action_ref_array($hook, $v['args']);
+            do_action_ref_array( $hook, $v['args'] );
+
+            // If the hook ran too long and another cron process stole the lock, quit.
+            if ( _get_cron_lock() != $doing_wp_cron )
+                return;
         }
     }
 }
 
+if ( _get_cron_lock() == $doing_wp_cron )
+    delete_transient( 'doing_cron' );
+
 die();

trunk/wp-includes/cache.php

@@ -103 +103 @@
  * @param int|string $key What the contents in the cache are called
  * @param string $group Where the cache contents are grouped
+ * @param bool $force Whether to force an update of the local cache from the persistent cache (default is false)
  * @return bool|mixed False on failure to retrieve contents or the cache
  *      contents on success
  */
-function wp_cache_get($key, $group = '') {
-    global $wp_object_cache;
-
-    return $wp_object_cache->get($key, $group);
+function wp_cache_get( $key, $group = '', $force = false ) {
+    global $wp_object_cache;
+
+    return $wp_object_cache->get( $key, $group, $force );
 }
 
@@ -404 +405 @@
      * @param int|string $key What the contents in the cache are called
      * @param string $group Where the cache contents are grouped
+     * @param string $force Whether to force a refetch rather than relying on the local cache (default is false)
      * @return bool|mixed False on failure to retrieve contents or the cache
      *      contents on success
      */
-    function get($key, $group = 'default') {
+    function get( $key, $group = 'default', $force = false) {
         if ( empty ($group) )
             $group = 'default';

trunk/wp-includes/cron.php

@@ -205 +205 @@
     * try to make this as atomic as possible by setting doing_cron switch
     */
-    $flag = get_transient('doing_cron');
-
-    if ( $flag > $local_time + 10*60 )
-        $flag = 0;
+    $lock = get_transient('doing_cron');
+
+    if ( $lock > $local_time + 10*60 )
+        $lock = 0;
 
     // don't run if another process is currently running it or more than once every 60 sec.
-    if ( $flag + 60 > $local_time )
+    if ( $lock + WP_CRON_LOCK_TIMEOUT > $local_time )
         return;
 
@@ -227 +227 @@
             return;
 
-        set_transient( 'doing_cron', $local_time );
+        $doing_wp_cron = $local_time;
+        set_transient( 'doing_cron', $doing_wp_cron );
 
         ob_start();
-        wp_redirect( add_query_arg('doing_wp_cron', '', stripslashes($_SERVER['REQUEST_URI'])) );
+        wp_redirect( add_query_arg('doing_wp_cron', $doing_wp_cron, stripslashes($_SERVER['REQUEST_URI'])) );
         echo ' ';
 
@@ -241 +242 @@
     }
 
-    set_transient( 'doing_cron', $local_time );
-
-    $cron_url = get_option( 'siteurl' ) . '/wp-cron.php?doing_wp_cron';
+    $doing_wp_cron = $local_time;
+    set_transient( 'doing_cron', $doing_wp_cron );
+
+    $cron_url = get_option( 'siteurl' ) . '/wp-cron.php?doing_wp_cron=' . $doing_wp_cron;
     wp_remote_post( $cron_url, array('timeout' => 0.01, 'blocking' => false, 'sslverify' => apply_filters('https_local_ssl_verify', true)) );
 }

trunk/wp-includes/default-constants.php

@@ -269 +269 @@
     if ( !defined('WP_POST_REVISIONS') )
         define('WP_POST_REVISIONS', true);
+
+    /**
+     * @since 3.3.0
+     */
+    if ( !defined( 'WP_CRON_LOCK_TIMEOUT' ) )
+        define('WP_CRON_LOCK_TIMEOUT', 60);  // In seconds
 }