Citus安装指导

1，集群规划

coordinate：协调节点，一般称为cn，存储所有元数据，不存实际数据。

2，配置pg网络策略

worker节点的pg_hba.conf配置:
# IPv4 local connections:
host    all             all             192.168.0.0/24            trust

3，安装citus

软件下载：（根据需求选择对应版本）

wget https://github.com/citusdata/citus/archive/v8.1.1.tar.gz

依赖软件包安装：

 yum install curl
 yum install curl-devel

citus安装：

# 安装
[root@localhost citus-8.1.1]# ./configure
[root@localhost citus-8.1.1]# make
[root@localhost citus-8.1.1]# make install

4，在worker节点安装 citus extension

[postgres@localhost ~]$ psql
psql (10.3)
Type "help" for help.
postgres=# \c test
You are now connected to database "test" as user "postgres"
.test=# create extension citus;

5，协调节点增加worker节点

#仅仅在协调节点（cn）上操作

#添加节点
test=# SELECT * from master_add_node('worker1', 5432);
test=# SELECT * from master_add_node('worker2', 5432);
#查看工作节点：
test=# SELECT * FROM master_get_active_worker_nodes();
node_name | node_port 
-----------+-----------
 worker2   |      5432
 worker4   |      5432
 worker1   |      5432
 worker3   |      5432
(4 rows)

6，创建分片表

#创建分片表
test=# create table shiptrack(gid serial primary key,tracktime timestamp without time zone,geom geometry(Point,4326));
#配置分片策略
#设置分片数，4个主机，设置分片4，每个主机一张表
test=# set citus.shard_count=4;
# 配置副本数
test=# set citus.shard_replication_factor=2;
test=# SELECT create_distributed_table('shiptrack', 'gid', 'hash');

# 查看分片分布
test=# SELECT * from pg_dist_shard_placement order by shardid, placementid;
 shardid | shardstate | shardlength | nodename | nodeport | placementid 
---------+------------+-------------+----------+----------+-------------
  102016 |          1 |           0 | worker1  |     5432 |          25
  102016 |          1 |           0 | worker2  |     5432 |          26
  102017 |          1 |           0 | worker2  |     5432 |          27
  102017 |          1 |           0 | worker3  |     5432 |          28
  102018 |          1 |           0 | worker3  |     5432 |          29
  102018 |          1 |           0 | worker4  |     5432 |          30
  102019 |          1 |           0 | worker4  |     5432 |          31
  102019 |          1 |           0 | worker1  |     5432 |          32

有4个worker，所以数据分片为4，每个分片，做两个副本。通过分片分布，如102016分布在worker1，worker2上，同理102017分布在worker2，worker3上。

参考手册：

https://github.com/citusdata/citus/releases