oracle – Pragma inline没有显示出明显的改善?
发布时间:2021-01-22 17:21:31 所属栏目:站长百科 来源:网络整理
导读:我已经了解了PRAGMA INLINE 11g功能,但我无法区分它是如何实际优化我的代码的. 我写了一段代码. create or replace package test12is procedure getdata (p_job IN emp.job%TYPE,p_total OUT number);end test12;/create or replace package body test12is P
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我已经了解了PRAGMA INLINE 11g功能,但我无法区分它是如何实际优化我的代码的. 我写了一段代码. create or replace package test12
is
procedure getdata (p_job IN emp.job%TYPE,p_total OUT number);
end test12;
/
create or replace package body test12
is
PROCEDURE total(p_empno IN EMP.EMPNO%TYPE,p_total OUT integer)
IS
BEGIN
select sal into p_total from emp where empno=p_empno;
END total;
procedure getdata (p_job IN emp.job%TYPE,p_total OUT number)
IS
type cur is ref cursor;
v_cur cur;
v_emp emp.empno%TYPE;
v_total integer:=0;
BEGIN
for i in 1..100000
loop
open v_cur for select empno from emp where job=p_job;
loop
fetch v_cur into v_emp;
exit when v_cur%notfound;
--PRAGMA INLINE(total,'YES');
total(v_emp,v_total);
p_total:=p_total+v_total;
end loop;
close v_cur;
end loop;
END getdata;
end test12;
/
declare
v_total integer;
v_start integer;
v_end integer;
begin
v_start:=DBMS_UTILITY.GET_TIME;
test12.getdata('CLERK',v_total);
v_end :=DBMS_UTILITY.GET_TIME;
v_total:=v_end-v_start;
dbms_output.put_line('time is '||v_total);
end;
/
现在,如果我在没有内联编译的情况下运行它会给我以下时间 First Run : time is 3573 Second Run: time is 3571 Third Run : time is 3554 现在,如果我使用pragma inline运行它会给我以下时间 First Run : time is 3471 Second Run: time is 3489 Third Run : time is 3482 但在这里我没有看到两者之间有任何显着差异.可能是什么原因? 解决方法调用程序所花费的时间几乎为0.这里优化的很少.我很惊讶你看到了任何进步. 99.9%的执行时间可能花在SQL上,而不是PL / SQL上.--Procedure that does almost nothing
create or replace procedure total(p_empno IN number,p_total OUT integer) is
begin
p_total := p_empno + 1;
end;
/
--Disable optimiziations
alter session set PLSQL_OPTIMIZE_LEVEL = 0;
--Only time the procedure calls
declare
v_test_out number;
v_start number;
v_end number;
begin
v_start:=DBMS_UTILITY.GET_TIME;
for i in 1 .. 100000 loop
total(i,v_test_out);
end loop;
v_end :=DBMS_UTILITY.GET_TIME;
dbms_output.put_line('time is '||to_char(v_end-v_start));
end;
/
time is 5
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