diff --git a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
index e6b8e3a..b192c46 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb
@@ -44,6 +44,9 @@ module ActiveRecord
         @query_cache_enabled = old
       end
 
+      # Clear the query cache. One reason you may wish to call this method explicitly is between queries that ask 
+      # the database to randomize results.  Otherwise the cache would see the same SQL query and repeatedly return 
+      # the same result each time, silently undermining the randomness you were expecting.
       def clear_query_cache
         @query_cache.clear if @query_cache
       end