Does all functions and procedures work this way ? (dbms_lock)

Question

hi guys,
all along, i thought..
begin
dbms_output.put_line('a');
dbms_output.put_line('b');
end;
when ranned, i will thought of oracle pl/sql interpreter reading the source line by line
as the steps below
- saw dbms_output.put_line('a') ... print a
- saw dbms_output.put_line('b'); ... print b
thats all..
but after using dbms_lock, i realise its abit different from how i thought ..
begin
dbms_output.put_line('a');
dbms_lock.sleep(10);
dbms_output.put_line('b');
end;
i would have to actually wait for 10 sec before i can see the result 'a' and 'b'..
so it seems to me
the interpreter would
1) see dbms_output.put_line('a'); -- know it is going to print 'a' but doesnt do that yet
2) see dbms_lock.sleep(10); -- sleep for 10 sec..
3) see dmbS_output.put_line('b') -- knows it is going to print 'b' but doesnt do that yet
4) see end; -- ok print 'a' and 'b'
so somehow , for returning result or printing.. it seems to have done so until the END of the block/procedure/function INSTEAD of intepreting line by line and executing it.
However, for dbms_lock.sleep(10), its seems to be interpreted and executed immediately in the midst of the block.
so can i conclude that
for returning/displaying result, it is done at the end of the block
for others, it is done during the block
am i right ?
Best Regards,
Noob

Answer 1

Thinking is always a good thing, but reading docs is helpful too. PL/SQL unit always runs on database server side and always as a unit. dbms_output.put_line('A') simply writes A to a buffer and PL/SQL unit continues to execute. when whole unit completes buffer has all lines written to it. Now client tool SQL*Plus in your case can read buffer content and display it. SQL*PLus does it based on SET SERVEROUTPUT ON/OFF command. I hope now you understand that DBMS_OUTPUT does not provide an interface to to display output on client box but rather store it in a buffer.
SY.