diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 8baef19030be6045104cbc2f865e66b703d50fae..66c61b5f4af80e49ba05b7be60541a6470c1de42 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -184,6 +184,7 @@ def []=(sql, key)
 
           def dealloc(key)
             @connection.query "DEALLOCATE #{key}" if connection_active?
+          rescue PG::Error
           end
 
           def connection_active?