CREATE SUBSCRIPTION
¶
You can use the CREATE SUBSCRIPTION
statement to
add a new subscription to the current cluster.
See also
Table of contents
Synopsis¶
CREATE SUBSCRIPTION subscription_name
CONNECTION 'conninfo'
PUBLICATION publication_name [, ...]
Description¶
Create a new subscription to one or more publications on a publisher. The subscription name must be distinct from the name of any existing subscription in the cluster. The subscription represents a replication connection to the publisher. A logical replication will be started on a publisher once the subscription is enabled, which is by default on creation.
Parameters¶
- subscription_name
The name of the new subscription.
- CONNECTION ‘conninfo’
The connection string to the publisher, which is a URL in the following format:
crate://host:[port]?params
Parameters are given in the
key=value
format and separated by&
. Example:crate://example.com?user=my_user&password=1234&sslmode=disable
Supported parameters:
mode
: Sets how the subscriber cluster communicates with the publisher cluster. Two modes are supported:sniff
(the default) andpg_tunnel
.In the
sniff
mode, the subscriber cluster will use the transport protocol to communicate with the other cluster and it will attempt to establish direct connections to each node of the publisher cluster. Theport
defaults to 4300.In the
sniff
mode, there can be multiplehost:port
pairs, separated by a comma. Parameters will be the same for all hosts. These hosts are used as initial seed nodes to discover all eligible nodes from the remote cluster. Example:crate://example.com:4310,123.123.123.123
In the
pg_tunnel
mode, the subscriber cluster will initiate the connection using the PostgreSQL wire protocol, and then proceed communicating via the transport protocol, but within the connection established via the PostgreSQL protocol. All requests from the subscriber cluster to the publisher cluster will get routed through a single node. The connection is only established to the first host listed in the connection string. Theport
defaults to 5432.Parameters supported with both modes:
user
: name of the user who connects to a publishing cluster. Required.password
: user password.Caution
The user specified in the connection string, must have
DQL
privileges on all tables of the publication on a publisher cluster. Tables, for which the user does not have theDQL
privilege, will not be replicated.Parameters supported in the
pg_tunnel
mode:sslmode
: Configures whether the connection should use SSL. You must have a working SSL setup for the PostgreSQL wire protocol on both the subscriber and publisher cluster.Allowed values are
prefer
,require
ordisable
. Defaults toprefer
.- PUBLICATION publication_name
Names of the publications on the publisher to subscribe to