Oracle undocumented trace parameters
Do you know that there are more than thirty not documented and hidden parameters for tracing?
You can find them with this query:
select ksppinm "Parameter Name", ksppstvl "Value", ksppstdf "Default", from x$ksppi x, x$ksppcv y where x.indx = y.indx and ksppinm like '/_%trace%' escape '/' ;
Note that Oracle 9i has about 26 parameters (if I remember right). Oracle 10g has 35 parameters. Not yet test on 11g, I’ll do it. Also some parameters are only RAC related as _ges_trace (for GES/GCS trace)

