Oracle Database Discussions

Hi Experts,

I have a question about understanding the Explain Plan output. I am on Oracle 11.2.0.2 on Linux. I use this command:

select * from table(dbms_xplan.display_cursor(null,null,'ALL allstats'));

In the output there is a section like this:

Column Projection Information (identified by operation id):
-----------------------------------------------------------

   2 - (#keys=1; upd=6,7; cmp=1,4,5,6,7,8,9,10,11,12,13,14,15,16; cpy=1,5,6,8) "A1"."CLNT_OID"[VARCHAR2,16], "G2"."CLNT_OID"[VARCHAR2,16]........

I dont' what this means and how this information is to be used. I did look at several presentations on Explain plan but I did not get explanation about this. Can someone explain what the above is and how this information is useful?

Thank you!

OrauserN