[20220104]in list 几种写法性能测试.txt

[20220104]in list 几种写法性能测试.txt

–//以前写过几种in list的写法,从来没有测试过这几种方法的性能测试看看.

1.环境:
SCOTT@book> @ver1
PORT_STRING                    VERSION        BANNER
—————————— ————– ——————————————————————————–
x86_64/Linux 2.4.xx            11.2.0.4.0     Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 – 64bit Production

create table job_times (sid number, time_ela number,method varchar2(20));

2.in list测试例子:
–//注:我的测试仅仅测试number类型列表,主要我们生产系统用的这类也最多,另外就是xmltable的字符列表估计比较麻烦.
–//也许下篇测试看看.

–//1.使用str2numlist,str2varlist函数,源代码在网上很容易找到.
CREATE OR REPLACE TYPE numtabletype AS TABLE OF NUMBER
/

CREATE OR REPLACE FUNCTION str2numlist (p_string IN VARCHAR2)
   RETURN numtabletype
AS
   v_str    LONG         DEFAULT p_string || “,”;
   v_n      NUMBER;
   v_data   numtabletype := numtabletype ();
BEGIN
   LOOP
      v_n := TO_NUMBER (INSTR (v_str, “,”));
      EXIT WHEN (NVL (v_n, 0) = 0);
      v_data.EXTEND;
      v_data (v_data.COUNT) := LTRIM (RTRIM (SUBSTR (v_str, 1, v_n – 1)));
      v_str := SUBSTR (v_str, v_n + 1);
   END LOOP;

   RETURN v_data;
END;
/

–//select * from table (cast(STR2NURLIST(:st2) as numtabletype));

–//2.使用xmltable,可能仅仅适合11g:
SQL> var a varchar2(60);
SQL> exec :a := “10,20”;
PL/SQL procedure successfully completed.

SQL> select * from dept where deptno in  (select (column_value).getnumberval() from xmltable(:a));
    DEPTNO DNAME          LOC
———- ————– ————-
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS

–//3.正则表达式例子:

SELECT *
  FROM dept
 WHERE deptno IN
 ( SELECT TO_NUMBER (REGEXP_SUBSTR ( “10,20” ,”[^,]+” ,1 ,LEVEL)) FROM DUAL CONNECT BY REGEXP_SUBSTR ( “10,20” ,”[^,]+” ,1 ,LEVEL) IS NOT NULL);

3.测试脚本:

$ seq -f “%-1.0f” 1e9 90000011 1e10|wc
    100     100    1100

$ seq -f “%-1.0f” 1e9 90000011 1e10 | paste -sd”,” >|aa.txt

$ cat m16.txt
set verify off
set linesize 32767
variable vmethod varchar2(20);
exec :vmethod := “&&2”;
insert into job_times values ( sys_context (“userenv”, “sid”) ,dbms_utility.get_time ,:vmethod) ;
commit ;

declare
    v_string varchar2(4000);
        l_count PLS_INTEGER;
begin
     v_string := “1000000000,1090000011,…,9910001089”;
     for i in 1 .. &&1 loop
         select count(*) into l_count from (select * from table (cast(str2numlist(v_string) as numtabletype)));
—         select count(*) into l_count from (select (column_value).getnumberval() from xmltable(v_string));
—       select count(*) into l_count from (select to_number (regexp_substr ( v_string ,”[^,]+” ,1 ,level)) from dual connect by regexp_substr ( v_string ,”[^,]+” ,1 ,level) is not null);
—       DBMS_OUTPUT.PUT_LINE (l_count);
    end loop;
end ;
/
update job_times set time_ela = dbms_utility.get_time – time_ela where sid=sys_context (“userenv”, “sid”) and method=:vmethod;
commit;
set linesize 270
quit

–//v_string 的值从前面的aa.txt复制过来,我截断了。

4.测试:
–//在测试开始前我猜测使用正则表达式最慢，使用函数应该最快。

$ zzdate ;sqlplus -s -l scott/book @m16.txt 1e6  str2numlist >/dev/null;zzdate
trunc(sysdate)+16/24+33/1440+03/86400 == 2022/01/04 16:33:03 == timestamp”2022-01-04 16:33:03″
trunc(sysdate)+16/24+40/1440+16/86400 == 2022/01/04 16:40:16 == timestamp”2022-01-04 16:40:16″

$ zzdate ;sqlplus -s -l scott/book @m16.txt 1e6  xmltable     >/dev/null;zzdate
trunc(sysdate)+16/24+41/1440+00/86400 == 2022/01/04 16:41:00 == timestamp”2022-01-04 16:41:00″
trunc(sysdate)+17/24+12/1440+47/86400 == 2022/01/04 17:12:47 == timestamp”2022-01-04 17:12:47″

$ zzdate ;sqlplus -s -l scott/book @m16.txt 1e6  regexp_substr>/dev/null;zzdate
trunc(sysdate)+17/24+18/1440+50/86400 == 2022/01/04 17:18:50 == timestamp”2022-01-04 17:18:50″
trunc(sysdate)+00/24+43/1440+43/86400 == 2022/01/05 00:43:43 == timestamp”2022-01-05 00:43:43″

METHOD                 COUNT(*) ROUND(AVG(TIME_ELA),0) SUM(TIME_ELA)
——————– ———- ———————- ————-
str2numlist                   1                  43286         43286
xmltable                      1                 190635        190635
regexp_substr                 1                2668927       2668927

–//没有想到正则表达式执行时间有点夸张，可以明显看出使用函数str2numlist最快。
–//还可以看出正则表达式是一个很耗CPU资源的操作，一些语句即使出现在select部分，输出多条记录对CPU资源但是影响也会很大。