Oracle Database Discussions

Hi,
All know that the switching between PL/SQL and SQL engine should be avoided if possible....
Is there any statistic/'wait event' which counts for them.....????
For example , when the system waits for a block to be read .. then the system updates appropriately the 'wait event' db_file_scattered_read

I have used the folllowing query:

SQL> select name from v$event_name where lower(name) like '%context%';
 
NAME
----------------------------------------------------------------
enq: KK - context

Note: I use DB10g v.2

Thanks...
Sim