What happens if a maintenance window closes before a job that collects optimizer statistics completes? 

Answer options:

A. The job is terminated and the gathered statistics are not saved.
B. The job is terminated but the gathered statistics are not published.
C. The job continues to run until all statistics are gathered.
D. The job is terminated and statistics for the remaining objects are collected the next time the maintenance window opens.

D

The stop_on_window_close attribute controls whether the GATHER_STATS_JOB continues when the maintenance window closes. The default setting for the stop_on_window_close attribute is TRUE, causing Scheduler to terminate GATHER_STATS_JOB when the maintenance window closes. The remaining objects are then processed in the next maintenance window. References: https://docs.oracle.com/cd/B19306_01/server.102/b14211/stats.htm#g49431