CREATE SUBSCRIPTION(7) PostgreSQL 17.4 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 logical-replication subscription. The
user that creates a subscription becomes the owner of the subscription.
The subscription name must be distinct from the name of any existing
subscription in the current database.
A subscription represents a replication connection to the publisher.
Hence, in addition to adding definitions in the local catalogs, this
command normally 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, unless the subscription is initially disabled.
To be able to create a subscription, you must have the privileges of
the pg_create_subscription role, as well as CREATE privileges on the
current database.
Additional information about subscriptions and logical replication as a
whole is available at Section 29.2 and Chapter 29.
PARAMETERS
subscription_name
The name of the new subscription.
CONNECTION 'conninfo'
The libpq connection string defining how to connect to the
publisher database. For details see Section 32.1.1.
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 control what happens during subscription
creation:
connect (boolean)
Specifies whether the CREATE SUBSCRIPTION command should
connect to the publisher at all. The default is true. Setting
this to false will force the values of create_slot, enabled and
copy_data to false. (You cannot combine setting connect to
false with setting create_slot, enabled, or copy_data to true.)
Since no connection is made when this option is false, no
tables are subscribed. To initiate replication, you must
manually create the replication slot, enable the failover if
required, enable the subscription, and refresh the
subscription. See Section 29.2.3 for examples.
create_slot (boolean)
Specifies whether the command should create the replication
slot on the publisher. The default is true.
If set to false, you are responsible for creating the
publisher's slot in some other way. See Section 29.2.3 for
examples.
enabled (boolean)
Specifies whether the subscription should be actively
replicating or whether it should just be set up but not started
yet. The default is true.
slot_name (string)
Name of the publisher's replication slot to use. The default is
to use the name of the subscription for the slot name.
Setting slot_name to NONE means there will be no replication
slot associated with the subscription. Such subscriptions must
also have both enabled and create_slot set to false. Use this
when you will be creating the replication slot later manually.
See Section 29.2.3 for examples.
When setting slot_name to a valid name and create_slot to
false, the failover property value of the named slot may differ
from the counterpart failover parameter specified in the
subscription. Always ensure the slot property failover matches
the counterpart parameter of the subscription and vice versa.
Otherwise, the slot on the publisher may behave differently
from what these subscription options say: for example, the slot
on the publisher could either be synced to the standbys even
when the subscription's failover option is disabled or could be
disabled for sync even when the subscription's failover option
is enabled.
The following parameters control the subscription's replication
behavior after it has been created:
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. Any initial table synchronization copy (see
copy_data) also uses the same format. Binary format can be
faster than the text format, but it is less portable across
machine architectures and PostgreSQL versions. Binary format is
very data type specific; for example, it will not allow copying
from a smallint column to an integer column, even though that
would work fine in text format. Even when this option is
enabled, only data types having binary send and receive
functions will be transferred in binary. Note that the initial
synchronization requires all data types to have binary send and
receive functions, otherwise the synchronization will fail (see
CREATE TYPE (CREATE_TYPE(7)) for more about send/receive
functions).
When doing cross-version replication, it could be that the
publisher has a binary send function for some data type, but
the subscriber lacks a binary receive function for that type.
In such a case, data transfer will fail, and the binary option
cannot be used.
If the publisher is a PostgreSQL version before 16, then any
initial table synchronization will use text format even if
binary = true.
copy_data (boolean)
Specifies whether to copy pre-existing data in the publications
that are being subscribed to when the replication starts. The
default is true.
If the publications contain WHERE clauses, it will affect what
data is copied. Refer to the Notes for details.
See Notes for details of how copy_data = true can interact with
the origin parameter.
streaming (enum)
Specifies whether to enable streaming of in-progress
transactions for this subscription. The default value is off,
meaning all transactions are fully decoded on the publisher and
only then sent to the subscriber as a whole.
If set to on, the incoming changes are written to temporary
files and then applied only after the transaction is committed
on the publisher and received by the subscriber.
If set to parallel, incoming changes are directly applied via
one of the parallel apply workers, if available. If no parallel
apply worker is free to handle streaming transactions then the
changes are written to temporary files and applied after the
transaction is committed. Note that if an error happens in a
parallel apply worker, the finish LSN of the remote transaction
might not be reported in the server log.
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.
two_phase (boolean)
Specifies whether two-phase commit is enabled for this
subscription. The default is false.
When two-phase commit is enabled, prepared transactions are
sent to the subscriber at the time of PREPARE TRANSACTION, and
are processed as two-phase transactions on the subscriber too.
Otherwise, prepared transactions are sent to the subscriber
only when committed, and are then processed immediately by the
subscriber.
The implementation of two-phase commit requires that
replication has successfully finished the initial table
synchronization phase. So even when two_phase is enabled for a
subscription, the internal two-phase state remains temporarily
"pending" until the initialization phase completes. See column
subtwophasestate of pg_subscription to know the actual
two-phase state.
disable_on_error (boolean)
Specifies whether the subscription should be automatically
disabled if any errors are detected by subscription workers
during data replication from the publisher. The default is
false.
password_required (boolean)
If set to true, connections to the publisher made as a result
of this subscription must use password authentication and the
password must be specified as a part of the connection string.
This setting is ignored when the subscription is owned by a
superuser. The default is true. Only superusers can set this
value to false.
run_as_owner (boolean)
If true, all replication actions are performed as the
subscription owner. If false, replication workers will perform
actions on each table as the owner of that table. The latter
configuration is generally much more secure; for details, see
Section 29.10. The default is false.
origin (string)
Specifies whether the subscription will request the publisher
to only send changes that don't have an origin or send changes
regardless of origin. Setting origin to none means that the
subscription will request the publisher to only send changes
that don't have an origin. Setting origin to any means that the
publisher sends changes regardless of their origin. The default
is any.
See Notes for details of how copy_data = true can interact with
the origin parameter.
failover (boolean)
Specifies whether the replication slots associated with the
subscription are enabled to be synced to the standbys so that
logical replication can be resumed from the new primary after
failover. The default is false.
When specifying a parameter of type boolean, the = value part can be
omitted, which is equivalent to specifying TRUE.
NOTES
See Section 29.10 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. See
Section 29.2.3 for examples. This is an implementation restriction that
might be lifted in a future release.
If any table in the publication has a WHERE clause, rows for which the
expression evaluates to false or null will not be published. If the
subscription has several publications in which the same table has been
published with different WHERE clauses, a row will be published if any
of the expressions (referring to that publish operation) are satisfied.
In the case of different WHERE clauses, if one of the publications has
no WHERE clause (referring to that publish operation) or the
publication is declared as FOR ALL TABLES or FOR TABLES IN SCHEMA, rows
are always published regardless of the definition of the other
expressions. If the subscriber is a PostgreSQL version before 15, then
any row filtering is ignored during the initial data synchronization
phase. For this case, the user might want to consider deleting any
initially copied data that would be incompatible with subsequent
filtering. Because initial data synchronization does not take into
account the publication publish parameter when copying existing table
data, some rows may be copied that would not be replicated using DML.
See Section 29.2.2 for examples.
Subscriptions having several publications in which the same table has
been published with different column lists are not supported.
We allow non-existent publications to be specified so that users can
add those later. This means pg_subscription can have non-existent
publications.
When using a subscription parameter combination of copy_data = true and
origin = NONE, the initial sync table data is copied directly from the
publisher, meaning that knowledge of the true origin of that data is
not possible. If the publisher also has subscriptions then the copied
table data might have originated from further upstream. This scenario
is detected and a WARNING is logged to the user, but the warning is
only an indication of a potential problem; it is the user's
responsibility to make the necessary checks to ensure the copied data
origins are really as wanted or not.
To find which tables might potentially include non-local origins (due
to other subscriptions created on the publisher) try this SQL query:
# substitute <pub-names> below with your publication name(s) to be queried
SELECT DISTINCT PT.schemaname, PT.tablename
FROM pg_publication_tables PT,
pg_subscription_rel PS
JOIN pg_class C ON (C.oid = PS.srrelid)
JOIN pg_namespace N ON (N.oid = C.relnamespace)
WHERE N.nspname = PT.schemaname AND
C.relname = PT.tablename AND
PT.pubname IN (<pub-names>);
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 17.4 2025 CREATE SUBSCRIPTION(7)
postgresql 17.4 - Generated Sat Mar 22 13:53:30 CDT 2025