we have created new local data storage while inheriting base class properties, have mapped new class properties to external table to resolve performance issues. 

but we are not able to add records to this new 'local data table' and even not able to add/remove columns.

In Logs, finding error - Optimization cannot be performed, the class is either abstract or belongs to a Pega-ruleset .

Also a warning message is getting displayed on Records tab : We are unable to create columns to match the new properties added.this will cause performance problems while using this data type.Please click here to fix this problem.

FYI - we are not using pega feature to create this external table as that option is disabled for us in pega , we are running DDL statement generated by pega to create table after creating Data Type rule.