Oracle中大批量删除数据的方法

最新推荐文章于 2017-04-10 14:59:50 发布

转载最新推荐文章于 2017-04-10 14:59:50 发布 · 1.6k 阅读

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#oracle #delete #sql #测试

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本文介绍了一种通过分批提交的方式批量删除数据库中海量数据的方法，并提供了具体的PL/SQL过程实现。该过程通过自制事务处理机制，实现了高效的数据删除操作。

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','10000');
Finished!
Totally 100000 records deleted!

PL/SQL procedure successfully completed.

Elapsed: 00:00:18.85
SQL> 
SQL> exec delBigTab('HS_DLF_DOWNLOG_HISTORY','NUMDLFLOGGUID < 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('HS_DLF_DOWNLOG_HISTORY','NUMDLFLOGGUID < 20000000','10000');
 
Finished!
Totally 6999977 records deleted!

PL/SQL procedure successfully completed.

Elapsed: 00:27:24.69
700万大约27分钟

以上过程仅供参考.