bionic (7) CREATE_SUBSCRIPTION.7.gz

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 33.1.1.

       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. 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.

           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.

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))