1.创建表

create table t1  
(
id varchar2(10),
name varchar2(20)
)
partition by hash(id)
(
partition p1,
partition p2,
partition p3
);

2.查看数据

insert into t1 values('p1',1);
insert into t1 values('p1',2);
insert into t1 values('p3',3);

3.查看数据

SQL> select * from t1;

ID NAME
------------------------------ ------------------------------------------------------------
p1 1
p1 2
p3 3

SQL> select * from t1 partition(p1);

ID NAME
------------------------------ ------------------------------------------------------------
p1 1
p1 2

SQL> select * from t1 partition(p2);

no rows selected

SQL> select * from t1 partition(p3);

ID NAME
------------------------------ ------------------------------------------------------------
p3 3

4.存储过程插入大量数据

declare
i number;
begin
for i in 1..1000000 loop
insert into t1 values(i,'name');
end loop;
commit;
end;
/

5.查看每个分区的数据,可以看出,存在数据倾斜。​

SQL> select count(1) from t1 partition(p1);

COUNT(1)
----------
249867

SQL> select count(1) from t1 partition(p2);

COUNT(1)
----------
500616

SQL> select count(1) from t1 partition(p3);

COUNT(1)
----------
249517

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Linux,oracle