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
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
postgres=# ALTER TABLE tbl_log DETACH PARTITION tbl_log_default; ALTER TABLE
2、创建想要的分区
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
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
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=#
总结
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