gistfile1.diff

diff --git a/lib/query_memcached.rb b/lib/query_memcached.rb
index c911388..715c47d 100644
--- a/lib/query_memcached.rb
+++ b/lib/query_memcached.rb
@@ -88,6 +88,7 @@ module ActiveRecord
       
     end
     
+if ActiveRecord::ConnectionAdapters.const_defined?( 'PostgreSQLAdapter' )  
     class PostgreSQLAdapter < AbstractAdapter
 
       def execute_with_clean_query_cache(*args)
@@ -103,7 +104,8 @@ module ActiveRecord
       alias_method_chain :execute, :clean_query_cache
       
     end
-    
+end
+
     module QueryCache
     
       # Enable the query cache within the block