实例讲解临时处理去重 80w 数据时夯死现象

SQL> select count() from tb_bj_banker_etl;

2552381

SQL> select count() from tb_bj_banker_etl where (id) in (select id from tb_bj_banker_etl group by id having count()>1) and rowid not in(select max(rowid) from tb_bj_banker_etl group by id having count()>1);

830099

SQL> delete from tb_bj_banker_etl where(id) in (select id from tb_bj_banker_etl group by id having count()>1) and rowid not in(select max(rowid) from tb_bj_banker_etl group by id having count()>1);

SQL> mit;

SELECT 
 A.OWNER,            --OBJECT所属用户 
 A.OBJECT_NAME,         --OBJECT名称 
 B.XIDUSN, 
 B.XIDSLOT, 
 B.XIDSQN, 
 B.SESSION_ID,          --锁表用户的session 
 B.ORACLE_USERNAME,       --锁表用户的Oracle用户名 
 B.OS_USER_NAME,         --锁表用户的操作系统登陆用户名 
 B.PROCESS, 
 B.LOCKED_MODE, 
 C.MACHINE,           --锁表用户的计算机名称 
 C.STATUS,            --锁表状态 
 C.SERVER, 
 C.SID, 
 C.SERIAL#, 
 C.PROGRAM            --锁表用户所用的数据库管理工具 
FROM 
 ALL_OBJECTS A, 
 V$LOCKED_OBJECT B, 
 SYS.GV_$SESSION C 
WHERE 
 A.OBJECT_ID = B.OBJECT_ID 
 AND B.PROCESS = C.PROCESS 
ORDER BY 1,2 

第一次 
delete from tb_bj_banker_etl where(id) in (select id from tb_bj_banker_etl group by id having count()>1) and rowid not in(select max(rowid) from tb_bj_banker_etl group by id having count()>1) and rownum<=100000; 
mit; 
 
第二次 
delete from tb_bj_banker_etl where(id) in (select id from tb_bj_banker_etl group by id having count()>1) and rowid not in(select max(rowid) from tb_bj_banker_etl group by id having count()>1) and rownum<=100000; 
mit; 
 
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第八次 
delete from tb_bj_banker_etl where(id) in (select id from tb_bj_banker_etl group by id having count()>1) and rowid not in(select max(rowid) from tb_bj_banker_etl group by id having count()>1); 
mit;