CREATE SUBSCRIPTION(7) PostgreSQL 14.15 Documentation CREATE SUBSCRIPTION(7)
NAME
CREATE_SUBSCRIPTION - define a new subscription
SYNOPSIS
CREATE SUBSCRIPTION subscription_name
CONNECTION 'conninfo'
PUBLICATION publication_name [, ...]
[ WITH ( subscription_parameter [= value] [, ... ] ) ]
DESCRIPTION
CREATE SUBSCRIPTION adds a new subscription for the current database.
The subscription name must be distinct from the name of any existing
subscription in the database.
The subscription represents a replication connection to the publisher.
As such this command does not only add definitions in the local
catalogs but also creates a replication slot on the publisher.
A logical replication worker will be started to replicate data for the
new subscription at the commit of the transaction where this command is
run.
Additional information about subscriptions and logical replication as a
whole is available at Section 31.2 and Chapter 31.
PARAMETERS
subscription_name
The name of the new subscription.
CONNECTION 'conninfo'
The connection string to the publisher. For details see
Section 34.1.1.
PUBLICATION publication_name
Names of the publications on the publisher to subscribe to.
WITH ( subscription_parameter [= value] [, ... ] )
This clause specifies optional parameters for a subscription. The
following parameters are supported:
copy_data (boolean)
Specifies whether the existing data in the publications that
are being subscribed to should be copied once the replication
starts. The default is true.
create_slot (boolean)
Specifies whether the command should create the replication
slot on the publisher. The default is true.
enabled (boolean)
Specifies whether the subscription should be actively
replicating, or whether it should be just setup but not started
yet. The default is true.
slot_name (string)
Name of the replication slot to use. The default behavior is to
use the name of the subscription for the slot name.
When slot_name is set to NONE, there will be no replication
slot associated with the subscription. This can be used if the
replication slot will be created later manually. Such
subscriptions must also have both enabled and create_slot set
to false.
synchronous_commit (enum)
The value of this parameter overrides the synchronous_commit
setting within this subscription's apply worker processes. The
default value is off.
It is safe to use off for logical replication: If the
subscriber loses transactions because of missing
synchronization, the data will be sent again from the
publisher.
A different setting might be appropriate when doing synchronous
logical replication. The logical replication workers report the
positions of writes and flushes to the publisher, and when
using synchronous replication, the publisher will wait for the
actual flush. This means that setting synchronous_commit for
the subscriber to off when the subscription is used for
synchronous replication might increase the latency for COMMIT
on the publisher. In this scenario, it can be advantageous to
set synchronous_commit to local or higher.
binary (boolean)
Specifies whether the subscription will request the publisher
to send the data in binary format (as opposed to text). The
default is false. Even when this option is enabled, only data
types that have binary send and receive functions will be
transferred in binary.
When doing cross-version replication, it could happen that the
publisher has a binary send function for some data type, but
the subscriber lacks a binary receive function for the type. In
such a case, data transfer will fail, and the binary option
cannot be used.
connect (boolean)
Specifies whether the CREATE SUBSCRIPTION should connect to the
publisher at all. Setting this to false will change default
values of enabled, create_slot and copy_data to false.
It is not allowed to combine connect set to false and enabled,
create_slot, or copy_data set to true.
Since no connection is made when this option is set to false,
the tables are not subscribed, and so after you enable the
subscription nothing will be replicated. It is required to run
ALTER SUBSCRIPTION ... REFRESH PUBLICATION in order for tables
to be subscribed.
streaming (boolean)
Specifies whether streaming of in-progress transactions should
be enabled for this subscription. By default, all transactions
are fully decoded on the publisher, and only then sent to the
subscriber as a whole.
NOTES
See Section 31.7 for details on how to configure access control between
the subscription and the publication instance.
When creating a replication slot (the default behavior), CREATE
SUBSCRIPTION cannot be executed inside a transaction block.
Creating a subscription that connects to the same database cluster (for
example, to replicate between databases in the same cluster or to
replicate within the same database) will only succeed if the
replication slot is not created as part of the same command. Otherwise,
the CREATE SUBSCRIPTION call will hang. To make this work, create the
replication slot separately (using the function
pg_create_logical_replication_slot with the plugin name pgoutput) and
create the subscription using the parameter create_slot = false. This
is an implementation restriction that might be lifted in a future
release.
EXAMPLES
Create a subscription to a remote server that replicates tables in the
publications mypublication and insert_only and starts replicating
immediately on commit:
CREATE SUBSCRIPTION mysub
CONNECTION 'host=192.168.1.50 port=5432 user=foo dbname=foodb'
PUBLICATION mypublication, insert_only;
Create a subscription to a remote server that replicates tables in the
insert_only publication and does not start replicating until enabled at
a later time.
CREATE SUBSCRIPTION mysub
CONNECTION 'host=192.168.1.50 port=5432 user=foo dbname=foodb'
PUBLICATION insert_only
WITH (enabled = false);
COMPATIBILITY
CREATE SUBSCRIPTION is a PostgreSQL extension.
SEE ALSO
ALTER SUBSCRIPTION (ALTER_SUBSCRIPTION(7)), DROP SUBSCRIPTION
(DROP_SUBSCRIPTION(7)), CREATE PUBLICATION (CREATE_PUBLICATION(7)),
ALTER PUBLICATION (ALTER_PUBLICATION(7))
PostgreSQL 14.15 2024 CREATE SUBSCRIPTION(7)
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