Citus Deployment
Citus is a distributed extension plugin for PostgreSQL. By default, Pigsty installs Citus but does not enable it. pigsty-citus.yml provides a config file case for deploying a Citus cluster. To allow Citus to, you need to modify the following parameters.
max_prepared_transaction: Modify to a value greater thanmax_connections, e.g. 800.pg_libs: Must containcitusand be placed in the top position.- You need to include the
citusextension plugin in the business database (but you can also manually install it viaCREATE EXTENSION).
Citus cluster sample config
#----------------------------------#
# cluster: citus coordinator
#----------------------------------#
pg-meta:
hosts:
10.10.10.10: { pg_seq: 1, pg_role: primary , pg_offline_query: true }
vars:
pg_cluster: pg-meta
vip_address: 10.10.10.2
pg_users: [ { name: citus , password: citus , pgbouncer: true , roles: [ dbrole_admin ] } ]
pg_databases: [ { name: meta , owner: citus , extensions: [ { name: citus } ] } ]
#----------------------------------#
# cluster: citus data nodes
#----------------------------------#
pg-node1:
hosts:
10.10.10.11: { pg_seq: 1, pg_role: primary }
vars:
pg_cluster: pg-node1
vip_address: 10.10.10.3
pg_users: [ { name: citus , password: citus , pgbouncer: true , roles: [ dbrole_admin ] } ]
pg_databases: [ { name: meta , owner: citus , extensions: [ { name: citus } ] } ]
pg-node2:
hosts:
10.10.10.12: { pg_seq: 1, pg_role: primary , pg_offline_query: true }
vars:
pg_cluster: pg-node2
vip_address: 10.10.10.4
pg_users: [ { name: citus , password: citus , pgbouncer: true , roles: [ dbrole_admin ] } ]
pg_databases: [ { name: meta , owner: citus , extensions: [ { name: citus } ] } ]
pg-node3:
hosts:
10.10.10.13: { pg_seq: 1, pg_role: primary , pg_offline_query: true }
vars:
pg_cluster: pg-node3
vip_address: 10.10.10.5
pg_users: [ { name: citus , password: citus , pgbouncer: true , roles: [ dbrole_admin ] } ]
pg_databases: [ { name: meta , owner: citus , extensions: [ { name: citus } ] } ]
Next, you need to refer to the Citus Multi-Node Deployment Guide, and on the Coordinator node, execute the following command to add a data node.
sudo su - postgres; psql meta
SELECT * from citus_add_node('10.10.10.11', 5432);
SELECT * from citus_add_node('10.10.10.12', 5432);
SELECT * from citus_add_node('10.10.10.13', 5432);
SELECT * FROM citus_get_active_worker_nodes();
node_name | node_port
-------------+-----------
10.10.10.11 | 5432
10.10.10.13 | 5432
10.10.10.12 | 5432
(3 rows)
After successfully adding data nodes, you can use the following command to create sample data tables on the coordinator and distribute them to each data node.
-- Declare a distributed table
CREATE TABLE github_events
(
event_id bigint,
event_type text,
event_public boolean,
repo_id bigint,
payload jsonb,
repo jsonb,
actor jsonb,
org jsonb,
created_at timestamp
) PARTITION BY RANGE (created_at);
-- Creating Distributed Tables
SELECT create_distributed_table('github_events', 'repo_id');
For more information about Citus, please refer to the Citus official doc.
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