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Oracle中大批量删除数据的方法(通过主键删除)

2012-07-31 21:24 471 查看

批量删除海量数据通常都是很复杂及缓慢的，方法也很多，但是通常的概念是:分批删除，逐次提交。

参见/article/11588775.html

下面是另一种删除过程，我的数据表可以通过主键删除，测试过Delete和For all两种方法，for all在这里并没有带来性能提高，所以仍然选择了批量直接删除。

首先创建一下过程，使用自制事务进行处理：

create or replace procedure delBigTab
(
p_TableName       in    varchar2,
p_Condition       in    varchar2,
p_Count        in    varchar2
)
as
pragma autonomous_transaction;
n_delete number:=0;
begin
while 1=1 loop
EXECUTE IMMEDIATE
'delete from '||p_TableName||' where '||p_Condition||' and rownum <= :rn'
USING p_Count;
if SQL%NOTFOUND then
exit;
else
n_delete:=n_delete + SQL%ROWCOUNT;
end if;
commit;
end loop;
commit;
DBMS_OUTPUT.PUT_LINE('Finished!');
DBMS_OUTPUT.PUT_LINE('Totally '||to_char(n_delete)||' records deleted!');
end;
/

开始：以下是删除过程及时间:

SQL> create or replace procedure delBigTab
2  (
3    p_TableName       in    varchar2,
4    p_Condition       in    varchar2,
5    p_Count        in    varchar2
6  )
7  as
8   pragma autonomous_transaction;
9   n_delete number:=0;
10  begin
11   while 1=1 loop
12     EXECUTE IMMEDIATE
13       'delete from '||p_TableName||' where '||p_Condition||' and rownum <= :rn'
14     USING p_Count;
15     if SQL%NOTFOUND then
16        exit;
17     else
18              n_delete:=n_delete + SQL%ROWCOUNT;
19     end if;
20     commit;
21   end loop;
22   commit;
23   DBMS_OUTPUT.PUT_LINE('Finished!');
24   DBMS_OUTPUT.PUT_LINE('Totally '||to_char(n_delete)||' records deleted!');
25  end;
26  /

Procedure created.

SQL> set timing on
SQL> select min(ID) from DEVICE_LOG;

MIN(NUMDLFLOGGUID)
------------------
11000000

Elapsed: 00:00:00.23
SQL> exec delBigTab('DEVICE_LOG','ID < 11100000','10000');

PL/SQL procedure successfully completed.

Elapsed: 00:00:18.54
SQL> select min(ID) from DEVICE_LOG;

MIN(ID)
------------------
11100000

Elapsed: 00:00:00.18
SQL> set serveroutput on
SQL> exec delBigTab('DEVICE_LOG','ID < 11200000','10000');
Finished!
Totally 96936 records deleted!

PL/SQL procedure successfully completed.

Elapsed: 00:00:18.61

10万记录大约19s

SQL> exec delBigTab('DEVICE_LOG','ID < 11300000','10000');
Finished!
Totally 100000 records deleted!

PL/SQL procedure successfully completed.

Elapsed: 00:00:18.62
SQL> exec delBigTab('DEVICE_LOG','ID < 11400000','10000');
Finished!
Totally 100000 records deleted!

PL/SQL procedure successfully completed.

Elapsed: 00:00:18.85
SQL>
SQL> exec delBigTab('DEVICE_LOG','ID < 13000000','10000');
Finished!
Totally 1000000 records deleted!

PL/SQL procedure successfully completed.

Elapsed: 00:03:13.87

100万记录大约3分钟

SQL> exec delBigTab('DEVICE_LOG','ID < 20000000','10000');

Finished!
Totally 6999977 records deleted!

PL/SQL procedure successfully completed.

Elapsed: 00:27:24.69

700万大约27分钟

转载eygle

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