optimizer_ ???

As a DBA should I be embarrassed?...
...besides optimizer_mode, I have never set any of these!
Suggestions, articles, links, etc?
Any "silver bullets" here?

SQL> show parameter opt

NAME                                 TYPE	VALUE
------------------------------------ -------	--------


...

optimizer_dynamic_sampling           integer	1
optimizer_features_enable            string	9.2.0
optimizer_index_caching              integer	0
optimizer_index_cost_adj             integer	100
optimizer_max_permutations           integer	2000
optimizer_mode                       string	CHOOSE

Thanks,

Chris Marquez
Oracle DBA
HEYMONitor(tm) - heymonitor.com
"Oracle Monitoring & Alerting Solution"

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