oracle 用库内分片的方法来 优化sql

转自落落公开课

create table t1 as select * from dba_objects;

create table t2 as select * from dba_objects;

CREATE TABLE P1(

HASH_VALUE NUMBER,

OWNER VARCHAR2(30),

OBJECT_NAME VARCHAR2(128),

SUBOBJECT_NAME VARCHAR2(30), 

OBJECT_ID NUMBER,

DATA_OBJECT_ID NUMBER,

OBJECT_TYPE VARCHAR2(19),

CREATED DATE,

LAST_DDL_TIME DATE,

TIMESTAMP VARCHAR2(19),

STATUS VARCHAR2(7),

TEMPORARY VARCHAR2(1),

GENERATED VARCHAR2(1),

SECONDARY VARCHAR2(1),

NAMESPACE NUMBER,

EDITION_NAME VARCHAR2(30)

)   

   PARTITION BY  list(HASH_VALUE)

(

partition p0 values (0),

partition p1 values (1),

partition p2 values (2),

partition p3 values (3),

partition p4 values (4)

)

CREATE TABLE P2(

HASH_VALUE NUMBER,

OWNER VARCHAR2(30),

OBJECT_NAME VARCHAR2(128),

SUBOBJECT_NAME VARCHAR2(30), 

OBJECT_ID NUMBER,

DATA_OBJECT_ID NUMBER,

OBJECT_TYPE VARCHAR2(19),

CREATED DATE,

LAST_DDL_TIME DATE,

TIMESTAMP VARCHAR2(19),

STATUS VARCHAR2(7),

TEMPORARY VARCHAR2(1),

GENERATED VARCHAR2(1),

SECONDARY VARCHAR2(1),

NAMESPACE NUMBER,

EDITION_NAME VARCHAR2(30)

)   

   PARTITION BY  list(HASH_VALUE)

(

partition p0 values (0),

partition p1 values (1),

partition p2 values (2),

partition p3 values (3),

partition p4 values (4)

)

delete t1 where object_id is null;

commit;

delete t1 where object_id is null;

commit;

insert into p1

select ora_hash(object_id,4), a.*  from t1 a;  ---工作中用append parallel并行插入

commit;

insert into p2

select ora_hash(object_id,4), a.*  from t2 a;  ---工作中用append parallel并行插入

commit;

--比较两个sql 的 

select * from t1,t2 where t1.object_id=t2.object_id;  -- 全表扫描

select * from  p1,p2 where p1.object_id=p2.object_id;  -- 用到hash join 和 分区