How to increase dbms_output buffer?

问题:

I tried to debug my dynamic query via dbms_output but seems like the query string is too long for dbms_output buffer.

I got :

ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at "SYS.DBMS_OUTPUT", line 148
ORA-06512: at line 1 

Any idea how to increase the buffer size ?

回答1:

You can Enable DBMS_OUTPUT and set the buffer size. The buffer size can be between 1 and 1,000,000.

dbms_output.enable(buffer_size IN INTEGER DEFAULT 20000);
exec dbms_output.enable(1000000);

Check this

EDIT

As per the comment posted by Frank and Mat, you can also enable it with Null

exec dbms_output.enable(NULL);

buffer_size : Upper limit, in bytes, the amount of buffered information. Setting buffer_size to NULL specifies that there should be no limit. The maximum size is 1,000,000, and the minimum is 2,000 when the user specifies buffer_size (NOT NULL).

回答2:

When buffer size gets full. There are several options you can try:

1) Increase the size of the DBMS_OUTPUT buffer to 1,000,000

2) Try filtering the data written to the buffer - possibly there is a loop that writes to DBMS_OUTPUT and you do not need this data.

3) Call ENABLE at various checkpoints within your code. Each call will clear the buffer.

DBMS_OUTPUT.ENABLE(NULL) will default to 20000 for backwards compatibility Oracle documentation on dbms_output

You can also create your custom output display.something like below snippets

create or replace procedure cust_output(input_string in varchar2 )
is 

   out_string_in long default in_string; 
   string_lenth number; 
   loop_count number default 0; 

begin 

   str_len := length(out_string_in);

   while loop_count < str_len
   loop 
      dbms_output.put_line( substr( out_string_in, loop_count +1, 255 ) ); 
      loop_count := loop_count +255; 
   end loop; 
end;

Link -Ref :Alternative to dbms_output.putline @ By: Alexander

回答3:

Here you go:

DECLARE
BEGIN
  dbms_output.enable(NULL); -- Disables the limit of DBMS
  -- Your print here !
END;