Unusable Indexes

To load data in a table efficiently, we can make Indexes as UNUSABLE. However, the TRUNCATE operation should be done before making the indexes unusable. If table is truncated after the indexes are made unusable, then it will have no effect. The TRUNCATE will automatically make the index USABLE. so the correct order to load data will be as follows:

• truncate the table
• set the indexes to unusable
• load the data
• rebuild the indexes