13 DEC 2016 10:48
13 DEC 2016 11:30
13 DEC 2016 12:00
13 DEC 2016 12:30
13 DEC 2016 13:00
13 DEC 2016 13:30
13 DEC 2016 14:00
14 DEC 2016 15:30
16 DEC 2016 17:30
16 DEC 2016 18:00
16 DEC 2016 18:30
16 DEC 2016 19:30
16 DEC 2016 20:00
19 DEC 2016 15:40

    SNAP_INTERVAL	        RETENTION	   TOPNSQL
+00000 00:30:00.0	+00010 00:00:00.0	       100

Active Session History (ASH) performed an emergency flush. This may mean that ASH is undersized. If emergency flushes are a recurring issue, you may consider increasing ASH size by setting the value of _ASH_SIZE to a sufficiently large value. Currently, ASH size is 33554432 bytes. Both ASH size and the total number of emergency flushes since instance startup can be monitored by running the following query:
 select total_size,awr_flush_emergency_count from v$ash_info;