diff --git a/classes/Memcached_DataObject.php b/classes/Memcached_DataObject.php
index f7cbb9d5b6..96f8d520ba 100644
--- a/classes/Memcached_DataObject.php
+++ b/classes/Memcached_DataObject.php
@@ -33,21 +33,41 @@ class Memcached_DataObject extends DB_DataObject
             $k = $keys[0];
             unset($i);
         }
-        $i = Memcached_DataObject::getcached($cls, $k, $v);
+        $i = self::getcached($cls, $k, $v);
         if ($i) {
             return $i;
         } else {
             $i = DB_DataObject::staticGet($cls, $k, $v);
             if ($i) {
                 $i->encache();
+            } else {
+                self::cachenull($cls, $k, $v);
             }
             return $i;
         }
     }
 
+    function cachenull($cls, $k, $v)
+    {
+        $c = self::memcache();
+        if (empty($c)) {
+            return;
+        }
+        $c->set(self::cacheKey($cls, $k, $v), null);
+    }
+
+    function multicachenull($cls, $kv)
+    {
+        $c = self::memcache();
+        if (empty($c)) {
+            return;
+        }
+        $c->set(self::multicachekey($cls, $kv), null);
+    }
+
     function &pkeyGet($cls, $kv)
     {
-        $i = Memcached_DataObject::multicache($cls, $kv);
+        $i = self::multicache($cls, $kv);
         if ($i) {
             return $i;
         } else {
@@ -58,6 +78,7 @@ class Memcached_DataObject extends DB_DataObject
             if ($i->find(true)) {
                 $i->encache();
             } else {
+                self::multicachenull($cls, $kv);
                 $i = null;
             }
             return $i;
@@ -67,6 +88,9 @@ class Memcached_DataObject extends DB_DataObject
     function insert()
     {
         $result = parent::insert();
+        if ($result) {
+            $this->encache();
+        }
         return $result;
     }
 
@@ -97,11 +121,11 @@ class Memcached_DataObject extends DB_DataObject
     }
 
     static function getcached($cls, $k, $v) {
-        $c = Memcached_DataObject::memcache();
+        $c = self::memcache();
         if (!$c) {
             return false;
         } else {
-            return $c->get(Memcached_DataObject::cacheKey($cls, $k, $v));
+            return $c->get(self::cacheKey($cls, $k, $v));
         }
     }
 
@@ -168,17 +192,23 @@ class Memcached_DataObject extends DB_DataObject
 
     function multicache($cls, $kv)
     {
-        ksort($kv);
-        $c = Memcached_DataObject::memcache();
+        $c = self::memcache();
         if (!$c) {
             return false;
         } else {
-            $pkeys = implode(',', array_keys($kv));
-            $pvals = implode(',', array_values($kv));
-            return $c->get(Memcached_DataObject::cacheKey($cls, $pkeys, $pvals));
+            return $c->get(self::multicachekey($cls, $kv));
         }
     }
 
+    function multicachekey($cls, $kv)
+    {
+        ksort($kv);
+        $pkeys = implode(',', array_keys($kv));
+        $pvals = implode(',', array_values($kv));
+
+        return self::cacheKey($cls, $pkeys, $pvals);
+    }
+
     function getSearchEngine($table)
     {
         require_once INSTALLDIR.'/lib/search_engines.php';
@@ -211,7 +241,7 @@ class Memcached_DataObject extends DB_DataObject
 
     static function cachedQuery($cls, $qry, $expiry=3600)
     {
-        $c = Memcached_DataObject::memcache();
+        $c = self::memcache();
         if (!$c) {
             $inst = new $cls();
             $inst->query($qry);