• Oracle中大批量删除数据的方法


    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
      (
        p_TableName       in    varchar2,
        p_Condition       in    varchar2,
        p_Count        in    varchar2
      )
      as
       pragma autonomous_transaction;
       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

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  • 原文地址:https://www.cnblogs.com/liuzhuqing/p/7480209.html
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