Stomp queue restructuring for mass scalability:

- Multiplexing queues into groups and for multiple sites.
- Sharing vs breakout configurable per site and per queue via $config['queue']['breakout']
- Detect how many times a message is redelivered, discard if it's killed too many daemons
 - count configurable with $config['queue']['max_retries']
 - can dump the items to files in $config['queue']['dead_letter_dir']

Queue daemon memory & resource leak fixes:
- avoid unnecessary reconnections to memcached server (switch persistent connections back in on second initialization, assuming it's child process)
- monkey-patch for leaky .ini loads in DB_DataObject::databaseStructure() - was leaking 200k per active switch
- applied leak fixes to Status_network as well, using intermediate base Safe_DataObject for both it and Memcache_DataObject

Misc queue fixes:
- correct handling of child processes exiting due to signal termination instead of regular exit
- shutdown instead of infinite respawn loop if we're already past the soft memory limit at startup
- Added --all option for xmppdaemon... still opens one xmpp connection per site that has xmpp active

Cache updates:
- add Cache::increment() method with native support for memcached atomic increment

1 files changed, 26 insertions, 0 deletions

diff --git a/lib/cache.php b/lib/cache.php
index 635c96ad4..b3ec7534f 100644
--- a/lib/cache.php
+++ b/lib/cache.php
@@ -158,6 +158,32 @@ class Cache
     }
 
     /**
+     * Atomically increment an existing numeric value.
+     * Existing expiration time should remain unchanged, if any.
+     *
+     * @param string  $key    The key to use for lookups
+     * @param int     $step   Amount to increment (default 1)
+     *
+     * @return mixed incremented value, or false if not set.
+     */
+    function increment($key, $step=1)
+    {
+        $value = false;
+        if (Event::handle('StartCacheIncrement', array(&$key, &$step, &$value))) {
+            // Fallback is not guaranteed to be atomic,
+            // and may original expiry value.
+            $value = $this->get($key);
+            if ($value !== false) {
+                $value += $step;
+                $ok = $this->set($key, $value);
+                $got = $this->get($key);
+            }
+            Event::handle('EndCacheIncrement', array($key, $step, $value));
+        }
+        return $value;
+    }
+
+    /**
      * Delete the value associated with a key
      *
      * @param string $key Key to delete