Spool sql in Siebel

I think in the first few days of working in Siebel you would know that to troubleshoot performance or visibilty issue with any data loads the first question any Siebel techie would ask , did you spool the sql?

To resolve any visibility issue yes you just need to add a switch /s and get the spooled sql. But if you are troubleshooting some preformance issue you need to set some session parameters for Siebel client running on Oracle CBO environment.

alter session set optimizer_mode = first_rows_10;
alter session set hash_join_enabled = false;
alter session set "_optimizer_sortmerge_join_enabled" = false;
alter session set "_optimizer_join_sel_sanity_check" = true;

After setting these parameters the execution time on the spooled file should sync with response time on Siebel application. Later..