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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Interesting PL/SQL Puzzle
Without knowing the actual code, I'd use dbms_profiler and run this test say a thousand time. Analysis of collected data will help you find the problem spots.
-----Original Message-----
Sent: Saturday, November 08, 2003 1:09 PM
To: Multiple recipients of list ORACLE-L
I have a weird problem. It seems that execution speed of pl/sql proc can slow down dramatically as the size of the proc goes up even if nothing gets executed.
Let me explain:
I have a proc that looks like:
Proc test_1 (p1 in out varchar2, p2 in out varchar2) as
<some declared variables>
begin
if condition1 then
<big block for string manipulation, two pages of code (substr, instr,
etc)>
end if;
if condition2 then
<another big block for string manipulation, two pages of code (substr,
instr, etc)>
end if;
end;
If I change the proc to do nothing by altering it this way:
Proc test_2 (p1 in out varchar2, p2 in out varchar2) as
<some declared variables>
begin
if false then
<big block for string manipulation>
end if;
if false then
<another big block for string manipulation>
end if;
end;
The execution speed goes up a little bit but is still at least 50 percent slower than if I change the proc by removing the code in the "if" clause, look below:
Proc test_3 (p1 in out varchar2, p2 in out varchar2) as
<some declared variables>
begin
if false then
null;
end if;
if false then
null;
end if;
end;
proc test_3 ran 30 million times in 9 minutes while test_2 ran in 20
minutes.
Also test_2 required more CPU resources while running.
Also I tried native compilation, which did not do a lot (only 10 % faster). When I looked at the C code generated by the native compilation, I was not very pleased the way native compilation works.
Does anybody have a clue why?
I tried to include the proc in a package and pin it but there was no difference.
Thanks
Waleed
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