Added cache for opening post id

boards/models/post.py

@@ -23,7 +23,7 b" APP_LABEL_BOARDS = 'boards'"
 
 CACHE_KEY_PPD = 'ppd'
 CACHE_KEY_POST_URL = 'post_url'
-CACHE_KEY_OPENING_POST = 'opening_post'
+CACHE_KEY_OPENING_POST = 'opening_post_id'
 
 POSTS_PER_DAY_RANGE = range(7)
 
@@ -253,7 +253,7 b' class Post(models.Model):'
         return self.referenced_posts.exists()
 
     def is_opening(self):
-        return self.get_thread().get_opening_post() == self
+        return self.get_thread().get_opening_post_id() == self.id
 
     def save(self, *args, **kwargs):
         """
@@ -418,14 +418,19 b' class Thread(models.Model):'
         Get first post of the thread
         """
 
-        # cache_key = CACHE_KEY_OPENING_POST + str(self.id)
-        # opening_post = cache.get(cache_key)
-        # if not opening_post:
         opening_post = self.get_replies()[0]
-            # cache.set(cache_key, opening_post)
 
         return opening_post
 
+    def get_opening_post_id(self):
+        cache_key = CACHE_KEY_OPENING_POST + str(self.id)
+        opening_post_id = cache.get(cache_key)
+        if not opening_post_id:
+            opening_post_id = self.get_replies()[0].id
+            cache.set(cache_key, opening_post_id)
+
+        return opening_post_id
+
     def __unicode__(self):
         return str(self.id)