CBO: Eliminating function calls

gistfile1.sql

SQL> create function xt_func(v varchar2) return varchar2 as
  2  begin
  3     dbms_output.put_line('Function fired! ['||v||']');
  4     return v;
  5  end;
  6  /

Function created.

SQL> create view xt_view as
  2  select dummy a, xt_func(dummy) f from dual
  3  /

View created.

SQL> select * from xt_view;

A   F
--- ----------
X   X

1 row selected.

Function fired! [X]

SQL> select a from xt_view;

A
---
X

1 row selected.