got pls-00201 when I call a package via public synonym in Oracle

Question

I created a package named sf_timer in sys, then I created a public synonym on this:

create or replace public synonym sf_timer for sys.sf_timer;
select * from all_synonyms where synonym_name = 'SF_TIMER';

Then I call this package from another user:

set serveroutput on
declare
  i integer;
  j integer;
begin
  sf_timer.start_timer;
  for i in 1..100000
  loop
    j := j +1;
  end loop;
  sf_timer.show_elapsed_time('Test 1');
end;
/

Unfortunately I got error below:

Error report:
ORA-06550: line 5, column 3:
PLS-00201: identifier 'SF_TIMER' must be declared
ORA-06550: line 5, column 3:
PL/SQL: Statement ignored
ORA-06550: line 10, column 3:
PLS-00201: identifier 'SF_TIMER' must be declared
ORA-06550: line 10, column 3:
PL/SQL: Statement ignored
06550. 00000 -  "line %s, column %s:\n%s"
*Cause:    Usually a PL/SQL compilation error.

I can see this public synonym from all_synonyms but I don't know why I cannot call the package in my schema.

Thanks in advance.

Answer 1

Have you granted permissions?

When running as SYS, do this...

GRANT EXECUTE ON SYS.SF_TIMER TO <user-you're-using>;

As a further note it's generally regarded as bad practise to create objects in the SYS schema :-)