高效删除大表重复记录的解决方案

---ddl before
CREATE bitmap index BIT_IDX_DATA_SRC on t1(DATA_SRC) NOLOGGING;
create index IDX_ID_Number on t1(ID_NUMBER) NOLOGGING;
ANALYZE INDEX BIT_IDX_DATA_SRC COMPUTE STATISTICS;
ANALYZE INDEX IDX_ID_Number COMPUTE STATISTICS;

--创建结构一致的中间永久表(DDL无undo非常节省资源)IN ('CBRC', 'CBRC File')  ----非常关键的一步
CREATE TABLE t1_mid tablespace TBS_LS_DATA
pctfree 10
initrans 1
maxtrans 255
storage
(
initial 64K
minextents 1
maxextents unlimited
)  AS  SELECT *
FROM t1 t1
WHERE t1.record_id = (SELECT MAX(t2.record_id)
FROM t2 t2
WHERE t2.data_src IN ('CBRC', 'CBRC File')
AND t1.id_number = t2.id_number)
AND t1.data_src IN ('CBRC', 'CBRC File');

--NOT IN ('CBRC', 'CBRC File')
INSERT INTO t1_mid SELECT * FROM blacklist a WHERE a.data_src NOT IN ('CBRC', 'CBRC File');
COMMIT;

-----ddl after

TRUNCATE TABLE t1;
DROP INDEX BIT_IDX_DATA_SRC;
DROP INDEX IDX_ID_Number;

--移动数据从中间表到最终表
INSERT INTO t1 SELECT * FROM blacklist_mid;

/*INSERT INTO t1 select * From (SELECT * FROM blacklist_mid  order by 1) where rownum<=1000000;*/
ANALYZE TABLE t1 COMPUTE STATISTICS; --收集统计信息

--清理环境
DROP TABLE t1_mid;