In reply to Nirmal.

Nirmal,You don't need to refresh your metadata every time your data change. When your data change it means you either add new records or modify old records; the data structure (table names, column names and types) stays the same. That is your metadata stays the same. You only need to change your metadata when you change your data structure or add new users or change their access level, etc. Frequency of your metadata updates has nothing to do with frequency of the data updates.