plsql - Oracle - ORA-06502: PL/SQL: numeric or value error (DBMS_OUTPUT)

Question

I implemented a function that returns clob data-type, and I would like to print the result in DBMS Output. Unfortunately, I am getting ORA-06502: PL/SQL: numeric or value error and I think it is due to the size of DBMS_OUTPUT.

This is the code.

DECLARE

    TYPE tp_col_array IS TABLE OF varchar2(32767); 
    FUNCTION my_fn (        
        p_in_proc_date IN varchar2)
        RETURN clob AS         
         vr_output_str clob;

        BEGIN            

        -- Detailed code hidden due to privacy. Sorry

        RETURN vr_output_str;

        EXCEPTION 
            WHEN LOGIN_DENIED
            THEN 
                DBMS_OUTPUT.PUT_LINE('Invalid username/password: logon denied');
        RETURN 'TEST Terminated';

    END my_fn;

BEGIN
    DBMS_OUTPUT.PUT_LINE(my_fn('31-AUG-14'));    
END;

Here are something that can help you to understand this issue
1) Added the following to set the size of buffer unlimited, but did not work..

DBMS_OUTPUT.ENABLE(NULL);

or

set serveroutput on size unlimited;

Related link: http://www.oracle-developer.net/display.php?id=327

2) It is noted that the size of vr_output_str is 75387, and that is why the return type is CLOB.

DBMS_LOB.getlength(vr_output_str); // =75387

3) I can solve the issue by doing the following, but I think this is not a good solution since it executed the function three times.

DBMS_OUTPUT.PUT_LINE(SUBSTR(my_fn ('31-AUG-14'), 1, 32767));
DBMS_OUTPUT.PUT_LINE(SUBSTR(my_fn ('31-AUG-14'), 32768, 32767));
DBMS_OUTPUT.PUT_LINE(SUBSTR(my_fn ('31-AUG-14'), 65536, 32767));

4) I am using Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production

Answer 1

You will not be able to print a clob using dbms_output.put_line directly if it is greater than 32767 bytes.

If this is the case you can create a procedure to iterate through the clob and print out one smaller chunk at a time. Such a procedure and test script is below:

declare 

  c clob;

  procedure print_clob( p_clob in clob ) is
      v_offset number default 1;
      v_chunk_size number := 10000;
  begin
      loop
          exit when v_offset > dbms_lob.getlength(p_clob);
          dbms_output.put_line( dbms_lob.substr( p_clob, v_chunk_size, v_offset ) );
          v_offset := v_offset +  v_chunk_size;
      end loop;
  end print_clob;


begin
  for i in 1..10000 loop
     c := c || 'test';
  end loop;
  --This will result in ora-06502
  --dbms_output.put_line(c);

  print_clob(c);

end;

Note that v_chunk_size must result in less than 32767 bytes being chunked at-a-time. If you encoding has 2 bytes per char you will need to use (32767/2).