diff --git a/app/controllers/comments_controller.rb b/app/controllers/comments_controller.rb
index 97036688e..9dcd753d9 100644
--- a/app/controllers/comments_controller.rb
+++ b/app/controllers/comments_controller.rb
@@ -78,7 +78,7 @@ private
   end
 
   def index_by_post
-    @posts = Post.where("last_comment_bumped_at IS NOT NULL").tag_match(params[:tags]).reorder("last_comment_bumped_at DESC").paginate(params[:page], :limit => 5, :search_count => params[:search])
+    @posts = Post.where("last_comment_bumped_at IS NOT NULL").tag_match(params[:tags]).reorder("last_comment_bumped_at DESC NULLS LAST").paginate(params[:page], :limit => 5, :search_count => params[:search])
     @posts.each # hack to force rails to eager load
     respond_with(@posts) do |format|
       format.html {render :action => "index_by_post"}
diff --git a/app/logical/post_query_builder.rb b/app/logical/post_query_builder.rb
index 552324017..6c5400321 100644
--- a/app/logical/post_query_builder.rb
+++ b/app/logical/post_query_builder.rb
@@ -419,7 +419,7 @@ class PostQueryBuilder
       relation = relation.order("posts.last_comment_bumped_at DESC NULLS LAST")
 
     when "comment_bumped_asc"
-      relation = relation.order("posts.last_comment_bumped_at ASC NULLS LAST")
+      relation = relation.order("posts.last_comment_bumped_at ASC NULLS FIRST")
 
     when "note"
       relation = relation.order("posts.last_noted_at DESC NULLS LAST")
diff --git a/db/migrate/20170519204506_fix_last_noted_at_index_on_posts.rb b/db/migrate/20170519204506_fix_last_noted_at_index_on_posts.rb
new file mode 100644
index 000000000..fb10551e5
--- /dev/null
+++ b/db/migrate/20170519204506_fix_last_noted_at_index_on_posts.rb
@@ -0,0 +1,11 @@
+class FixLastNotedAtIndexOnPosts < ActiveRecord::Migration
+  def up
+    Post.without_timeout do
+      remove_index :posts, column: :last_comment_bumped_at
+      add_index :posts, :last_comment_bumped_at, order: "DESC NULLS LAST"
+
+      remove_index :posts, column: :last_noted_at
+      add_index :posts, :last_noted_at, order: "DESC NULLS LAST"
+    end
+  end
+end
diff --git a/db/structure.sql b/db/structure.sql
index 9869c8562..1df387bc2 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -6896,14 +6896,14 @@ CREATE INDEX index_posts_on_image_width ON posts USING btree (image_width);
 -- Name: index_posts_on_last_comment_bumped_at; Type: INDEX; Schema: public; Owner: -
 --
 
-CREATE INDEX index_posts_on_last_comment_bumped_at ON posts USING btree (last_comment_bumped_at);
+CREATE INDEX index_posts_on_last_comment_bumped_at ON posts USING btree (last_comment_bumped_at DESC NULLS LAST);
 
 
 --
 -- Name: index_posts_on_last_noted_at; Type: INDEX; Schema: public; Owner: -
 --
 
-CREATE INDEX index_posts_on_last_noted_at ON posts USING btree (last_noted_at);
+CREATE INDEX index_posts_on_last_noted_at ON posts USING btree (last_noted_at DESC NULLS LAST);
 
 
 --
@@ -7545,3 +7545,5 @@ INSERT INTO schema_migrations (version) VALUES ('20170512221200');
 
 INSERT INTO schema_migrations (version) VALUES ('20170515235205');
 
+INSERT INTO schema_migrations (version) VALUES ('20170519204506');
+