Cpu costing is off (consider enabling it)...

I came across this message while checking an SQL statement during a performace check for a table.

Cpu costing is off (consider enabling it)

Curiosity made me go around an do some research and seems like theres no recommendations on the SAP side and very little info over all of the usage of parameter _optimizer_cost_model and its side effects.. As far as I can read that parameter affects dbms_stats.gather_system_stats.

There is info that points to performace improvement by using paremeter _optimizer_cost_model = cpu but I can't find any documenation that mentions that is supported by SAP or that is indeed recommended (or not).

Any thought's on this?

Database is Oracle 11.2.0.3

Regards, Juan