Oracle中大批量删除数据的方法(转)
参考：http://www.eygle.com/archives/2005/04/oracleoeouaeeae.html
感觉这篇文章不错，转来做笔记，以备不时之需。

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。
下面是我的删除过程，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;
/

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(NUMDLFLOGGUID) from HS_DLF_DOWNLOG_HISTORY;

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

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

PL/SQL procedure successfully completed.

Elapsed: 00:00:18.54
SQL> select min(NUMDLFLOGGUID) from HS_DLF_DOWNLOG_HISTORY;

MIN(NUMDLFLOGGUID)
------------------
          11100000

Elapsed: 00:00:00.18
SQL> set serveroutput on
SQL> exec delBigTab('HS_DLF_DOWNLOG_HISTORY','NUMDLFLOGGUID < 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('HS_DLF_DOWNLOG_HISTORY','NUMDLFLOGGUID < 11300000','10000');
Finished!
Totally 100000 records deleted!

PL/SQL procedure successfully completed.

Elapsed: 00:00:18.62
SQL> exec delBigTab('HS_DLF_DOWNLOG_HISTORY','NUMDLFLOGGUID < 11400000'