When I temporarily change the retention hour of extract tail to only 1 hour, I want it to take effect immediately.
[oracle@test dirprm]$ vi mgr.prm
purgeoldextracts ./dirdat/*, usecheckpoints, minkeephours 1
So I use refresh, a GGSCI command, to make it updated online.
[oracle@test dirprm]$ cd ..
[oracle@test ogg]$ ./ggsci
GGSCI (test) 2> refresh mgr
Sending REFRESH request to MANAGER ...
Mgr Params Updated
The manager will purge the extract trail in 10 minutes.