openGauss每日一练第8天|学习openGauss分区表

学习目标

学习openGauss分区表

分区表是把逻辑上的一张表根据某种方案分成几张物理块进行存储，这张逻辑上的表称之为分区表，物理块称之为分区。

分区表是一张逻辑表，不存储数据，数据实际是存储在分区上的。

课程学习

连接openGauss

#第一次进入等待15秒
#数据库启动中...
su - omm
gsql -r

1.创建分区表

–范围分区表

create table update_table
(
        c1 int,
        c2 CHAR(2)
)
partition by range (c1)
(
        partition update_table_p0 values less than (50),
        partition update_table_p1 values less than (100),
        partition update_table_p2 values less than (150)
);

–查看分区表信息

\d+ update_table;
select * from pg_partition;

–插入数据

insert into update_table values (1, 'a'), (50, 'b'), (100, 'c');

–超出范围的数据会报错

insert into update_table values (150, 'd');

–查看各区上的数据

select * from update_table partition(update_table_p0);

2.创建分区

alter table update_table add partition update_table_p3 values less than (200);
insert into update_table values (150, 'd');

3.修改分区属性

alter table update_table rename partition update_table_p1 to update_table_p1_1;

4.删除分区

alter table update_table drop partition update_table_p0;

5.删除分区表

drop table update_table;

课程作业

1.创建一个含有5个分区的范围分区表store，在每个分区中插入记录

omm=# create table store
omm-# (
omm(#         c1 int,
omm(#         c2 CHAR(2)
omm(# )
omm-# partition by range (c1)
omm-# (
omm(#         partition store_p0 values less than (50),
omm(#         partition store_p1 values less than (100),
omm(#         partition store_p2 values less than (150),
omm(#         partition store_p3 values less than (200),
omm(#         partition store_p4 values less than (250)
omm(# );
CREATE TABLE
omm=# insert into store values (2, 'a');
INSERT 0 1
omm=# insert into store values (60, 'b');
INSERT 0 1
omm=# insert into store values (120, 'c');
INSERT 0 1
omm=# insert into store values (170, 'd');
INSERT 0 1
omm=# insert into store values (230, 'e');
INSERT 0 1

2.查看分区1上的数据

omm=# select * from store partition(store_p0);
 c1 | c2 
----+----
  2 | a 
(1 row)

3.重命名分区2

omm=# alter table store rename partition store_p1 to store_p1_1;
ALTER TABLE

4.删除分区5

omm=# alter table store drop partition store_p4;
ALTER TABLE

5.增加分区6

omm=# alter table store add partition store_p5 values less than (300);
ALTER TABLE

6.在系统表pg_partition中查看分区信息

omm=# select * from pg_partition;
  relname   | parttype | parentid | rangenum | intervalnum | partstrategy | relfilenode | reltablespace | relpages | reltuples | relallvisible | reltoastrelid | re
ltoastidxid | indextblid | indisusable | reldeltarelid | reldeltaidx | relcudescrelid | relcudescidx | relfrozenxid | intspnum | partkey | intervaltablespace | int
erval | boundaries | transit |                    reloptions                     | relfrozenxid64 
------------+----------+----------+----------+-------------+--------------+-------------+---------------+----------+-----------+---------------+---------------+---
------------+------------+-------------+---------------+-------------+----------------+--------------+--------------+----------+---------+--------------------+----
------+------------+---------+---------------------------------------------------+----------------
 store      | r        |    16397 |        0 |           0 | r            |           0 |             0 |        0 |         0 |             0 |             0 |   
 store_p0   | p        |    16397 |        0 |           0 | r            |       16401 |             0 |        0 |         0 |             0 |             0 |   
          0 |          0 | t           |             0 |           0 |              0 |            0 | 9325         |          |         |                    |    
          0 |          0 | t           |             0 |           0 |              0 |            0 | 0            |          | 1       |                    |    
      |            |         | {orientation=row,compression=no,wait_clean_gpi=n} |              0
 store_p2   | p        |    16397 |        0 |           0 | r            |       16403 |             0 |        0 |         0 |             0 |             0 |   
          0 |          0 | t           |             0 |           0 |              0 |            0 | 9325         |          |         |                    |    
      | {150}      |         | {orientation=row,compression=no}                  |           9325
 store_p3   | p        |    16397 |        0 |           0 | r            |       16404 |             0 |        0 |         0 |             0 |             0 |   
      | {50}       |         | {orientation=row,compression=no}                  |           9325
 store_p1_1 | p        |    16397 |        0 |           0 | r            |       16402 |             0 |        0 |         0 |             0 |             0 |   
          0 |          0 | t           |             0 |           0 |              0 |            0 | 9325         |          |         |                    |    
      | {200}      |         | {orientation=row,compression=no}                  |           9325
          0 |          0 | t           |             0 |           0 |              0 |            0 | 9325         |          |         |                    |    
      | {100}      |         | {orientation=row,compression=no}                  |           9325
 store_p5   | p        |    16397 |        0 |           0 | r            |       16406 |             0 |        0 |         0 |             0 |             0 |   
          0 |          0 | t           |             0 |           0 |              0 |            0 | 9333         |          |         |                    |    
      | {300}      |         | {orientation=row,compression=no}                  |           9333
(6 rows)

7.删除分区表

omm=# drop table store;
DROP TABLE