PostgreSQL12.5中分区表的一些操作介绍_F11 - 专业站长和开发者的学习网站

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PostgreSQL12.5中分区表的一些操作介绍

PostgreSQL 来源：互联网作者：F11站长开发者发布时间：2022-08-12 15:34:48 人浏览

摘要

1、创建一个有DEFAULT的分区表 1、先创建主表 1 2 3 4 5 6 7 8 9 10 11 12 13 14 create table tbl_log ( id serial, create_time timestamp(0) without time zone, remark char(1) ) PARTITION BY RANGE (create_time); #因为是serial类型

1、创建一个有DEFAULT的分区表

1、先创建主表

create table tbl_log

(

id serial,

create_time timestamp(0) without time zone,

remark char(1)

) PARTITION BY RANGE (create_time);

#因为是serial类型，自增的所以会自动创建一个序列

postgres=# \d

List of relations

Schema | Name | Type | Owner

--------+----------------+-------------------+----------

public | tbl_log | partitioned table | postgres

public | tbl_log_id_seq | sequence | postgres

(7 rows)

2、如果没有创建分区就直接插入数据会报错

postgres=# INSERT INTO tbl_log(id, create_time, remark) VALUES (1, '2018-02-01', 'a');

ERROR: no partition of relation "tbl_log" found for row

DETAIL: Partition key of the failing row contains (create_time) = (2018-02-01 00:00:00).

postgres=#

3、创建分区

#包括左边1.1，不包括2.1

CREATE TABLE tbl_log_p201801 PARTITION OF tbl_log FOR VALUES FROM ('2018-01-01') TO ('2018-02-01');

CREATE TABLE tbl_log_p201802 PARTITION OF tbl_log FOR VALUES FROM ('2018-02-01') TO ('2018-03-01');

CREATE TABLE tbl_log_p201803 PARTITION OF tbl_log FOR VALUES FROM ('2018-03-01') TO ('2018-04-01');

CREATE TABLE tbl_log_default PARTITION OF tbl_log DEFAULT;

INSERT INTO tbl_log(id, create_time, remark) VALUES (1, '2018-02-01', 'a');

INSERT INTO tbl_log(id, create_time, remark) VALUES (2, '2018-03-01', 'b');

INSERT INTO tbl_log(id, create_time, remark) VALUES (3, '2018-04-01', 'd');

INSERT INTO tbl_log(id, create_time, remark) VALUES (4, '2020-07-01', 'c');

4、查看分区情况

postgres=# select * from tbl_log;

id | create_time | remark

----+---------------------+--------

1 | 2018-02-01 00:00:00 | a

2 | 2018-03-01 00:00:00 | b

3 | 2018-04-01 00:00:00 | d

4 | 2020-07-01 00:00:00 | c

(4 rows)

postgres=# select * from tbl_log_p201801;

id | create_time | remark

----+-------------+--------

(0 rows)

postgres=# select * from tbl_log_p201802;

id | create_time | remark

----+---------------------+--------

1 | 2018-02-01 00:00:00 | a

(1 row)

postgres=# select * from tbl_log_p201803;

id | create_time | remark

----+---------------------+--------

2 | 2018-03-01 00:00:00 | b

(1 row)

postgres=# select * from tbl_log_default;

id | create_time | remark

----+---------------------+--------

3 | 2018-04-01 00:00:00 | d

4 | 2020-07-01 00:00:00 | c

(2 rows)

postgres=#

2、有default 分区，再加分区

因为有default 分区，再加分区，所以会报错

1 2	postgres=# CREATE TABLE tbl_log_p201804 PARTITION OF tbl_log FOR VALUES FROM ('2018-04-01') TO ('2018-05-01'); ERROR: updated partition constraint for default partition "tbl_log_default" would be violated by some row

解决办法：

以上添加分区报错，需要解绑default分区，之后再添加，如下

1、解绑Default分区

1 2	postgres=# ALTER TABLE tbl_log DETACH PARTITION tbl_log_default; ALTER TABLE

2、创建想要的分区

1 2	postgres=# CREATE TABLE tbl_log_p201804 PARTITION OF tbl_log FOR VALUES FROM ('2018-04-01') TO ('2018-05-01'); CREATE TABLE

3、分区创建成功，分区创建之后需把DEFAULT分区连接。

连接DEFAULT分区报错，如下:

postgres=# ALTER TABLE tbl_log ATTACH PARTITION tbl_log_default DEFAULT;

ERROR: partition constraint is violated by some row

postgres=# INSERT INTO tbl_log_p201804 SELECT * FROM tbl_log_default;

ERROR: new row for relation "tbl_log_p201804" violates partition constraint

DETAIL: Failing row contains (4, 2020-07-01 00:00:00, c).

因为tbl_log_default分区内有2018-04-01的数据，把这个数据从tbl_log_default中导出到对应的分区，并清理tbl_log_default中的对应的数据

postgres=# INSERT INTO tbl_log_p201804 SELECT * FROM tbl_log_default where create_time>='2018-04-01' and create_time<'2018-05-01';

INSERT 0 1

postgres=# delete from tbl_log_default where create_time>='2018-04-01' and create_time<'2018-05-01';

DELETE 1

4、再次连接DEFAULT分区成功

1 2	postgres=# ALTER TABLE tbl_log ATTACH PARTITION tbl_log_default DEFAULT; ALTER TABLE

3、没有default的分区

创建没有default的分区，当插入的数据超过规划好的分区的时候会报错

1、创建1月份分区

create table tbl_log2

(

id serial,

create_time timestamp(0) without time zone,

remark char(1)

) PARTITION BY RANGE (create_time);

CREATE TABLE tbl_log2_p201801 PARTITION OF tbl_log2 FOR VALUES FROM ('2018-01-01') TO ('2018-02-01');

插入2月的数据就会报错

postgres=# INSERT INTO tbl_log2(id, create_time, remark) VALUES (1, '2018-01-01', 'a');

INSERT 0 1

postgres=# INSERT INTO tbl_log2(id, create_time, remark) VALUES (1, '2018-02-01', 'a');

ERROR: no partition of relation "tbl_log2" found for row

DETAIL: Partition key of the failing row contains (create_time) = (2018-02-01 00:00:00).

4、给分区表ddl

4.1、在原来没有主键的分区表加主键

结论：

1、在主表加主键，主键为仅仅想要的主键，会报错，需要用想要的主键+分区键组合为主键

2、分区表可以单独添加主键

1.1、在主表加主键，主键为仅仅想要的主键，报错如下 must include all partitioning columns

postgres=# alter table tbl_log add primary key(id);

ERROR: unique constraint on partitioned table must include all partitioning columns

DETAIL: PRIMARY KEY constraint on table "tbl_log" lacks column "create_time" which is part of the partition key.

postgres=# alter table tbl_log add primary key(id)

1.2、在主表添加主键需要是想要的主键+分区键

postgres=# alter table tbl_log add primary key (id,create_time);

ALTER TABLE

postgres=# \d tbl_log

Partitioned table "public.tbl_log"

Column | Type | Collation | Nullable | Default

-------------+--------------------------------+-----------+----------+-------------------------------------

id | integer | | not null | nextval('tbl_log_id_seq'::regclass)

create_time | timestamp(0) without time zone | | not null |

remark | character(1) | | |

name | character varying(2) | | |

Partition key: RANGE (create_time)

Indexes:

"tbl_log_pkey" PRIMARY KEY, btree (id, create_time)

Number of partitions: 5 (Use \d+ to list them.)

postgres=# \d tbl_log_p201801

Table "public.tbl_log_p201801"

Column | Type | Collation | Nullable | Default

-------------+--------------------------------+-----------+----------+-------------------------------------

id | integer | | not null | nextval('tbl_log_id_seq'::regclass)

create_time | timestamp(0) without time zone | | not null |

remark | character(1) | | |

name | character varying(2) | | |

Partition of: tbl_log FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2018-02-01 00:00:00')

Indexes:

"tbl_log_p201801_pkey" PRIMARY KEY, btree (id, create_time)

1.3、可以给分区表单独添加主键

postgres=# alter table tbl_log_p201801 add primary key (id);

ALTER TABLE

postgres=# \d tbl_log_p201801

Table "public.tbl_log_p201801"

Column | Type | Collation | Nullable | Default

-------------+--------------------------------+-----------+----------+-------------------------------------

id | integer | | not null | nextval('tbl_log_id_seq'::regclass)

create_time | timestamp(0) without time zone | | |

remark | character(1) | | |

name | character varying(2) | | |

Partition of: tbl_log FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2018-02-01 00:00:00')

Indexes:

"tbl_log_p201801_pkey" PRIMARY KEY, btree (id)

postgres=#

4.2、创建分区表时，就指定主键

主键不包括分区键，报错提示must include all partitioning columns

create table tbl_log2

(

id int,

create_time timestamp(0) without time zone,

remark char(1),

primary key (id)

);

ERROR: unique constraint on partitioned table must include all partitioning columns

DETAIL: PRIMARY KEY constraint on table "tbl_log2" lacks column "create_time" which is part of the partition key.

修改语句，添加分区键也为主键，创建成功

create table tbl_log2

(

id int,

create_time timestamp(0) without time zone,

remark char(1),

primary key (id,create_time)

) PARTITION BY RANGE (create_time);

CREATE TABLE

4.3、分区表加字段，修改字段

1、加字段，可以成功添加，在主表加字段，分区表会自动添加

postgres=# alter table tbl_log add name varchar(2);

ALTER TABLE

postgres=# \d tbl_log;

Partitioned table "public.tbl_log"

Column | Type | Collation | Nullable | Default

-------------+--------------------------------+-----------+----------+-------------------------------------

id | integer | | not null | nextval('tbl_log_id_seq'::regclass)

create_time | timestamp(0) without time zone | | |

remark | character(1) | | |

name | character varying(2) | | |

Partition key: RANGE (create_time)

Number of partitions: 5 (Use \d+ to list them.)

postgres=# \d tbl_log_p201801;

Table "public.tbl_log_p201801"

Column | Type | Collation | Nullable | Default

-------------+--------------------------------+-----------+----------+-------------------------------------

id | integer | | not null | nextval('tbl_log_id_seq'::regclass)

create_time | timestamp(0) without time zone | | |

remark | character(1) | | |

name | character varying(2) | | |

Partition of: tbl_log FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2018-02-01 00:00:00')

2、直接在分区表加字段会报错

1 2	postgres=# alter table tbl_log_p201801 add name2 varchar(2); ERROR: cannot add column to a partition

3、修改字段

postgres=# alter table tbl_log alter column remark type varchar(10);

ALTER TABLE

postgres=# \d tbl_log;

Partitioned table "public.tbl_log"

Column | Type | Collation | Nullable | Default

-------------+--------------------------------+-----------+----------+-------------------------------------

id | integer | | not null | nextval('tbl_log_id_seq'::regclass)

create_time | timestamp(0) without time zone | | not null |

remark | character varying(10) | | |

name | character varying(2) | | |

Partition key: RANGE (create_time)

Indexes:

"tbl_log_pkey" PRIMARY KEY, btree (id, create_time)

Number of partitions: 5 (Use \d+ to list them.)

postgres=# \d tbl_log_p201801

Table "public.tbl_log_p201801"

Column | Type | Collation | Nullable | Default

-------------+--------------------------------+-----------+----------+-------------------------------------

id | integer | | not null | nextval('tbl_log_id_seq'::regclass)

create_time | timestamp(0) without time zone | | not null |

remark | character varying(10) | | |

name | character varying(2) | | |

Partition of: tbl_log FOR VALUES FROM ('2018-01-01 00:00:00') TO ('2018-02-01 00:00:00')

Indexes:

"tbl_log_p201801_pkey" PRIMARY KEY, btree (id, create_time)

postgres=#

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原文链接 : https://blog.csdn.net/weixin_42583514/article/details/123063420

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