Set the AUTO_CLOSE Database Option to OFF
This rule checks whether the AUTO_ CLOSE option is set OFF for SQL Server Standard and Enterprise editions. When AUTO_CLOSE is set ON, this option can cause performance degradation on frequently accessed databases because of the increased overhead of opening and closing the database after each connection. AUTO_CLOSE also flushes the procedure cache after each connection.
Best Practices Recommendations
If a database is accessed frequently, set the AUTO_CLOSE option to OFF for the database.