diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb
index aa9e133fe41b72c8369cfabeb7cf6ff7a325d8b8..801cb23362b900ec3b085ac261e808bc2dc2dbcc 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb
@@ -89,10 +89,23 @@ def clear_active_connections!
       
       # Clears the cache which maps classes 
       def clear_reloadable_connections!
-        @@active_connections.each do |name, conn|
-          if conn.requires_reloading?
-            conn.disconnect!
-            @@active_connections.delete(name)
+        if @@allow_concurrency
+          # With concurrent connections @@active_connections is
+          # a hash keyed by thread id.
+          @@active_connections.each do |thread_id, conns|
+            conns.each do |name, conn|
+              if conn.requires_reloading?
+                conn.disconnect!
+                @@active_connections[thread_id].delete(name)
+              end
+            end
+          end
+        else
+          @@active_connections.each do |name, conn|
+            if conn.requires_reloading?
+              conn.disconnect!
+              @@active_connections.delete(name)
+            end
           end
         end
       end