LAG EXTRACT to determine a true lag time between Extract and the data source.
LAG EXTRACT calculates the lag time more precisely than
INFO EXTRACT because it communicates with Extract directly, rather than reading a checkpoint position in the trail.
For Extract, lag is the difference, in seconds, between the time that a record was processed by Extract (based on the system clock) and the timestamp of that record in the data source.
LAG EXTRACT group_name
The name of an Extract group or a wildcard (*) to specify multiple groups. For example, T* determines lag time for all Extract groups whose names start with T.