AWR_SNAPSHOT_TIME_OFFSET

Property	Description
Parameter type	Integer
Default value	There is no offset by default
Modifiable	`ALTER SYSTEM`
Range of values	0 - 3599, or the special value 1000000
Basic	No
Oracle RAC	Multiple instances should use the same value

AWR_SNAPSHOT_TIME_OFFSET specifies an offset for the AWR snapshot start time.

AWR snapshots normally start at the top of the hour (12:00, 1:00, 2:00, and so on). This parameter allows DBAs to specify an offset for the AWR snapshot start time.

This is a useful parameter to avoid CPU spikes from multiple instances all starting their AWR snapshots at the same time. If you have a large system with many instances on it (like many Exadata installations), and you are experiencing such CPU spikes, this parameter can be very useful.

The parameter is specified in seconds. Normally, you set it to a value less than 3600. If you set the special value 1000000 (1,000,000), you get an automatic mode, in which the offset is based on the database name.

The automatic mode is an effective way of getting a reasonable distribution of offset times when you have a very large number of instances running on the same node.