Updated to a supported idmapper version. Added a method for calculating the cache usage of the idmapper, and tied it to the @system command.

src/utils/idmapper/manager.py

@@ -1,6 +1,26 @@
 from django.db.models.manager import Manager
+try:
+    from django.db import router
+except:
+    pass
+
 
 class SharedMemoryManager(Manager):
+    # CL: this ensures our manager is used when accessing instances via
+    # ForeignKey etc. (see docs)
+    use_for_related_fields = True
+
+    # CL: in the dev version of django, ReverseSingleRelatedObjectDescriptor
+    # will call us as:
+    #     rel_obj = rel_mgr.using(db).get(**params)
+    # We need to handle using, or the get method will be called on a vanilla
+    # queryset, and we won't get a change to use the cache.
+    def using(self, alias):
+        if alias == router.db_for_read(self.model):
+            return self
+        else:
+            return super(SharedMemoryManager, self).using(alias)
+
     # TODO: improve on this implementation
     # We need a way to handle reverse lookups so that this model can
     # still use the singleton cache, but the active model isn't required
@@ -8,8 +28,13 @@ class SharedMemoryManager(Manager):
     def get(self, **kwargs):
         items = kwargs.keys()
         inst = None
-        if len(items) == 1 and items[0] in ('pk', self.model._meta.pk.attname):
-            inst = self.model.get_cached_instance(kwargs[items[0]])
+        if len(items) == 1:
+            # CL: support __exact
+            key = items[0]
+            if key.endswith('__exact'):
+                key = key[:-len('__exact')]
+            if key in ('pk', self.model._meta.pk.attname):
+                inst = self.model.get_cached_instance(kwargs[items[0]])
         if inst is None:
             inst = super(SharedMemoryManager, self).get(**kwargs)
-        return inst
+        return inst