WRH$_ACTIVE_SESSION_HISTORY table Does Not Get Purged

Yesterday I received tablespace alert “Sysaux tablespace threshold reached 95%”

I saw the sysaux tablespace total size is around 4.5 GB.

I think sysaux tablespace growth is abnormal.
I have checked AWR retention is 7 days. It means AWR keeps last 7 days historical records, remaining things are purged automatically.

V$sysaux _occupants are also showed “AWR used more space in sysaux tablespace”.
Sys.WRH$_ACTIVE_SESSION_HISTORY tables & indexes are huge objects in sysaux tablespace.

I have verified how many snapshot details stored in automatic workload repository.
It’s stored around 4000 snapshot details & last 6 months AWR reports (Snapshot interval is 1 hour).

AWR didn’t purge the Sys.WRH$_ACTIVE_SESSION_HISTORY tables.

Finally I manually purged the AWR snapshot & reclaimed 1.5 GB free space in sysaux tablespace.

exec
DBMS_WORKLOAD_REPOSITORY.drop_snapshot_range (
low_snap_id => 1500,
high_snap_id => 5500);

Why AWR didn’t purge automatically?

Please refer below metalink notes for more details: (10.2.0.1 to 10.2.0.5)
WRH$_ACTIVE_SESSION_HISTORY Does Not Get Purged [ID 387914.1]