1.建立主表
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CREATE TABLE part_tab (c1 int, c2 int,name varchar(20)) PARTITION BY RANGE (c1);
2.建立子分区表
CREATE TABLE part1 PARTITION OF part_tab FOR VALUES FROM (0) TO (100);
CREATE TABLE part2 PARTITION OF part_tab FOR VALUES FROM (100) TO (200);
3.附加已经存在的表作为主表的子分区
1).attach partition（附加表分区）
-- 执行附加分区命令前，要附加分区的表必须已经存在
create table ext_part(c1 int not null, c2 int,name varchar(20));
附加分区前，要附加分区的数据必须满足主表分区列的约束条件，如果不满足条件则无法把新的分区附加到主表。
ALTER TABLE part_tab ATTACH PARTITION ext_part FOR VALUES FROM (400) to (500);
2).detach partition（摘除分区表）
--解除分区绑定，解除后\d+命令显示分区表中就不包含已经摘除的分区。
ALTER TABLE part_tab DETACH PARTITION ext_part;
4.准备外部服务器(子表服务器)
$ psql testdb
# create table fpart3 (c1 int not null, c2 int,name varchar(20));
# create table fpart4 (c1 int not null, c2 int,name varchar(20));
testdb=# \dt
List of relations
Schema | Name | Type | Owner
--------+--------+-------+----------
public | fpart3 | table | postgres
public | fpart4 | table | postgres
(2 rows)
testdb=#
5.增加扩展
$ psql testdb
# create extension postgres_fdw;
# create server server_remote_226 foreign data wrapper postgres_fdw options(host '172.16.3.226',port '5432',dbname 'testdb');
# create user mapping for postgres server server_remote_226 options(user 'postgres',password '111111');
testdb=# \des+
List of foreign servers
Name | Owner | Foreign-data wrapper | Access privileges | Type | Version | FDW Options
| Description
-------------------+----------+----------------------+-------------------+------+---------+-----------------------------------------
------------+-------------
server_remote_226 | postgres | postgres_fdw | | | | (host '172.16.3.226', port '5432', dbnam
e 'testdb') |
(1 row)
testdb=# \deu+
List of user mappings
Server | User name | FDW Options
-------------------+-----------+----------------------------------------
server_remote_226 | postgres | ("user" 'postgres', password '111111')
(1 row)
6.建立外部表
CREATE FOREIGN TABLE part3 PARTITION OF part_tab FOR VALUES FROM (200) TO (300) SERVER server_remote_226 options (schema_name 'public',table_name 'fpart3');
CREATE FOREIGN TABLE part4 PARTITION OF part_tab FOR VALUES FROM (300) TO (400) SERVER server_remote_226 options (schema_name 'public',table_name 'fpart4');
testdb=# \det+
List of foreign tables
Schema | Table | Server | FDW Options | Description
--------+-------+-------------------+---------------------------------------------+-------------
public | part3 | server_remote_226 | (schema_name 'public', table_name 'fpart3') |
public | part4 | server_remote_226 | (schema_name 'public', table_name 'fpart4') |
(2 rows)
testdb=#
7.插入测试数据
-- 外部分区表无法通过主表插入数据,需要通过外部表方式插入
testdb=# insert into part_tab values(1,1,'Chris'),(101,101,'Peter'),(201,201,'William'),(301,301,'Feng');
ERROR: cannot route inserted tuples to a foreign table
testdb=#
数据分别在各自服务器插入
主表服务器,通过主表插入本地分区数据
# insert into part_tab values(1,1,'Chris'),(101,101,'Peter');
INSERT 0 2
testdb=#
外部表服务器，通过外部表分别插入
testdb=# insert into part3 values(201,201,'William');
INSERT 0 1
testdb=# insert into part4 values(301,301,'Feng');
INSERT 0 1
testdb=#
testdb=#
testdb=# select * from part_tab ;
c1 | c2 | name
-----+-----+---------
1 | 1 | Chris
101 | 101 | Peter
201 | 201 | William
301 | 301 | Feng
(4 rows)
testdb=#
外部分区表对违反分区列的插入无约束机制，这样的数据可以任意插入。
testdb=# insert into part4 values(201,301,'Feng');
INSERT 0 1
testdb=# select * from part_tab ;
c1 | c2 | name
-----+-----+---------
1 | 1 | Chris
101 | 101 | Peter
201 | 201 | William
301 | 301 | Feng
201 | 301 | Feng
(5 rows)
testdb=#
8.添加主键和约束
-- 主表分区列不支持建立主键约束
testdb=# alter table part_tab add constraint part_tab_c1_pkey primary key(c1);
ERROR: primary key constraints are not supported on partitioned tables
LINE 1: alter table part_tab add constraint part_tab_c1_pkey primary...
^
testdb=#
--- 约束、索引需在子表添加
--主表服务器
testdb=# alter table part1 add constraint part1_c1_pkey primary key(c1);
ALTER TABLE
testdb=# alter table part2 add constraint part2_c1_pkey primary key(c1);
ALTER TABLE
testdb=#
testdb=# create index idx_part1_c1_c2_name on part1(c1,c2,name);
CREATE INDEX
testdb=# create index idx_part2_c1_c2_name on part2(c1,c2,name);
CREATE INDEX
testdb=#
testdb=# \d part1
Table "public.part1"
Column | Type | Collation | Nullable | Default
--------+-----------------------+-----------+----------+---------
c1 | integer | | not null |
c2 | integer | | |
name | character varying(20) | | |
Partition of: part_tab FOR VALUES FROM (0) TO (100)
Indexes:
"part1_c1_pkey" PRIMARY KEY, btree (c1)
"idx_part1_c1_c2_name" btree (c1, c2, name)
testdb=#
testdb=# \d part2
Table "public.part2"
Column | Type | Collation | Nullable | Default
--------+-----------------------+-----------+----------+---------
c1 | integer | | not null |
c2 | integer | | |
name | character varying(20) | | |
Partition of: part_tab FOR VALUES FROM (100) TO (200)
Indexes:
"part2_c1_pkey" PRIMARY KEY, btree (c1)
"idx_part2_c1_c2_name" btree (c1, c2, name)
testdb=#
-- 子表服务器
testdb=# alter table fpart3 add constraint fpart3_c1_pkey primary key(c1);
ALTER TABLE
testdb=# alter table fpart4 add constraint fpart4_c1_pkey primary key(c1);
ALTER TABLE
testdb=# create index idx_fpart3_c1_c2_name on fpart3(c1,c2,name);
CREATE INDEX
testdb=# create index idx_fpart4_c1_c2_name on fpart4(c1,c2,name);
CREATE INDEX
testdb=#
testdb=# \d fpart3
Table "public.fpart3"
Column | Type | Collation | Nullable | Default
--------+-----------------------+-----------+----------+---------
c1 | integer | | not null |
c2 | integer | | |
name | character varying(20) | | |
Indexes:
"fpart3_c1_pkey" PRIMARY KEY, btree (c1)
"idx_fpart3_c1_c2_name" btree (c1, c2, name)
testdb=#
testdb=# \d fpart4
Table "public.fpart4"
Column | Type | Collation | Nullable | Default
--------+-----------------------+-----------+----------+---------
c1 | integer | | not null |
c2 | integer | | |
name | character varying(20) | | |
Indexes:
"fpart4_c1_pkey" PRIMARY KEY, btree (c1)
"idx_fpart4_c1_c2_name" btree (c1, c2, name)
testdb=#
9.查询语句的分区修剪
testdb=# explain analyze select * from part_tab where c1=1;
QUERY PLAN
------------------------------------------------------------------------------------------------------
Append (cost=0.00..1.01 rows=1 width=66) (actual time=0.009..0.009 rows=1 loops=1)
-> Seq Scan on part1 (cost=0.00..1.01 rows=1 width=66) (actual time=0.008..0.009 rows=1 loops=1)
Filter: (c1 = 1)
Planning time: 0.234 ms
Execution time: 0.027 ms
(5 rows)
testdb=# explain analyze select * from part_tab where c1=101;
QUERY PLAN
------------------------------------------------------------------------------------------------------
Append (cost=0.00..1.01 rows=1 width=66) (actual time=0.025..0.028 rows=1 loops=1)
-> Seq Scan on part2 (cost=0.00..1.01 rows=1 width=66) (actual time=0.024..0.026 rows=1 loops=1)
Filter: (c1 = 101)
Planning time: 0.271 ms
Execution time: 0.066 ms
(5 rows)
testdb=# explain analyze select * from part_tab where c1=201;
QUERY PLAN
--------------------------------------------------------------------------------------------------------------
Append (cost=100.00..121.47 rows=5 width=66) (actual time=2.179..2.180 rows=1 loops=1)
-> Foreign Scan on part3 (cost=100.00..121.47 rows=5 width=66) (actual time=2.178..2.178 rows=1 loops=1)
Planning time: 0.308 ms
Execution time: 3.551 ms
(4 rows)
testdb=# explain analyze select * from part_tab where c1=301;
QUERY PLAN
--------------------------------------------------------------------------------------------------------------
Append (cost=100.00..121.47 rows=5 width=66) (actual time=1.218..1.219 rows=1 loops=1)
-> Foreign Scan on part4 (cost=100.00..121.47 rows=5 width=66) (actual time=1.217..1.218 rows=1 loops=1)
Planning time: 0.312 ms
Execution time: 2.178 ms
(4 rows)
testdb=# explain analyze select * from part_tab where c1<201;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------
Append (cost=0.00..129.46 rows=305 width=66) (actual time=0.014..2.881 rows=2 loops=1)
-> Seq Scan on part1 (cost=0.00..1.01 rows=1 width=66) (actual time=0.014..0.015 rows=1 loops=1)
Filter: (c1 < 201)
-> Seq Scan on part2 (cost=0.00..1.01 rows=1 width=66) (actual time=0.009..0.009 rows=1 loops=1)
Filter: (c1 < 201)
-> Foreign Scan on part3 (cost=100.00..127.44 rows=303 width=66) (actual time=2.855..2.855 rows=0 loops=1)
Planning time: 0.234 ms
Execution time: 3.884 ms
(8 rows)
testdb=#
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