collectStatMode

The time at which ApsaraDB RDS collects the statistics of the new instance.

• Before: ApsaraDB RDS collects the statistics of the new instance before the switchover to ensure service stability. If the original instance contains a large amount of data, the upgrade may require a long period of time.

• After: ApsaraDB RDS collects the statistics of the new instance after the switchover to accelerate the upgrade. If you access tables for which no statistics are generated, the query plans that you specify may be inaccurately executed. In addition, your database service may be unavailable during peak hours.

NOTE If you set the SwitchOver parameter to false, the value Before specifies that ApsaraDB RDS collects the statistics of the new instance before the new instance starts to process read and write requests, and the value After specifies that ApsaraDB RDS collects the statistics of the new instance after the new instance starts to process read and write requests.