citus的快速开始

准备

• docker
• citus最新版本（docker pull citusdata/citus）

docker网络

docker network create --subnet=172.72.9.0/24 citus-test
docker network ls

启动citus服务

1. 启动协调节点

docker run -dit --name citus-cod -p 5433:5432 -e POSTGRES_PASSWORD=123456 \
    -v /Users/zjw/Documents/docker/citus-cod:/var/lib/postgresql/data \
    --net=citus-test \
    citusdata/citus -c listen_addresses='*' -c shared_preload_libraries='citus

2. 启动两个工作节点

docker run -dit --name citus-work10 -e POSTGRES_PASSWORD=123456 \
    -v /Users/zjw/Documents/docker/citus-work10:/var/lib/postgresql/data \
    --net=citus-test \
    citusdata/citus -c listen_addresses='*' -c shared_preload_libraries='citus'
docker run -dit --name citus-work11 -e POSTGRES_PASSWORD=123456 \
    -v /Users/zjw/Documents/docker/citus-work11:/var/lib/postgresql/data \
    --net=citus-test \
    citusdata/citus -c listen_addresses='*' -c shared_preload_libraries='citus'

添加节点

进入psql，添加节点并查看节点个数

docker  exec -it citus-cod psql -U postgres
select * from master_add_node('citus-worker10', 5432);
select * from master_add_node('citus-work11', 5432);
select * from master_get_active_worker_nodes();

测试

1. 创建表

create table student(
	id int PRIMARY KEY,
	name varchar(20)
);

2. 插入数据

insert into student(id, name) values(1, 'zhangsan');
insert into student(id, name) values(2, 'lisi');
insert into student(id, name) values(3, 'wangwu');
insert into student(id, name) values(4, 'zhaoliu');

3. 设置副本数为2

postgres=# set citus.shard_replication_factor=2;

4. 设置student为分布表

postgres=# select create_distributed_table('student', 'id');

显示默认分片数

postgres=#  show citus.shard_count;

查看分片

postgres=# select * from pg_dist_shard;
postgres=# select * from pg_dist_shard_placement;

更改分片数

postgres=# select alter_distributed_table('student', shard_count:=2, cascade_to_colocated:=true);
NOTICE:  creating a new table for public.student
NOTICE:  moving the data of public.student
NOTICE:  dropping the old public.student
NOTICE:  renaming the new table to public.student
 alter_distributed_table
-------------------------

(1 row)

查看分片位置

postgres=# select get_shard_id_for_distribution_column('student', 1);
 get_shard_id_for_distribution_column
--------------------------------------
                               102040
(1 row)