CREATE PUBLICATION

CREATE PUBLICATION
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CREATE PUBLICATION — define a new publication

Synopsis

CREATE PUBLICATION name
    [ FOR TABLE [ ONLY ] table_name [ * ] [, ...]
      | FOR ALL TABLES ]
    [ WITH ( publication_parameter [= value] [, ... ] ) ]

Description

CREATE PUBLICATION adds a new publication into the current database. The publication name must be distinct from the name of any existing publication in the current database.

A publication is essentially a group of tables whose data changes are intended to be replicated through logical replication. See Section 29.1 for details about how publications fit into the logical replication setup.

Parameters

name

The name of the new publication.

FOR TABLE

Specifies a list of tables to add to the publication. If ONLY is specified before the table name, only that table is added to the publication. If ONLY is not specified, the table and all its descendant tables (if any) are added. Optionally, * can be specified after the table name to explicitly indicate that descendant tables are included. This does not apply to a partitioned table, however. The partitions of a partitioned table are always implicitly considered part of the publication, so they are never explicitly added to the publication.

Only persistent base tables and partitioned tables can be part of a publication. Temporary tables, unlogged tables, foreign tables, and regular views cannot be part of a publication.

When a partitioned table is added to a publication, all of its existing and future partitions are implicitly considered to be part of the publication. So, even operations that are performed directly on a partition are also published via publications that its ancestors are part of.

FOR ALL TABLES

Marks the publication as one that replicates changes for all tables in the database, including tables created in the future.

WITH ( publication_parameter [= value] [, ... ] )

This clause specifies optional parameters for a publication. The following parameters are supported:

publish (string)

This parameter determines which DML operations will be published by the new publication to the subscribers. The value is comma-separated list of operations. The allowed operations are insert, update, delete, and truncate. The default is to publish all actions, and so the default value for this option is 'insert, update, delete, truncate'.

publish_via_partition_root (boolean)

This parameter determines whether changes in a partitioned table (or on its partitions) contained in the publication will be published using the identity and schema of the partitioned table rather than that of the individual partitions that are actually changed; the latter is the default. Enabling this allows the changes to be replicated into a non-partitioned table or a partitioned table consisting of a different set of partitions.

If this is enabled, TRUNCATE operations performed directly on partitions are not replicated.

Notes

If neither FOR TABLE nor FOR ALL TABLES is specified, then the publication starts out with an empty set of tables. That is useful if tables are to be added later.

The creation of a publication does not start replication. It only defines a grouping and filtering logic for future subscribers.

To create a publication, the invoking user must have the CREATE privilege for the current database. (Of course, superusers bypass this check.)

To add a table to a publication, the invoking user must have ownership rights on the table. The FOR ALL TABLES clause requires the invoking user to be a superuser.

The tables added to a publication that publishes UPDATE and/or DELETE operations must have REPLICA IDENTITY defined. Otherwise those operations will be disallowed on those tables.

For an INSERT ... ON CONFLICT command, the publication will publish the operation that actually results from the command. So depending of the outcome, it may be published as either INSERT or UPDATE, or it may not be published at all.

ATTACHing a table into a partition tree whose root is published using a publication with publish_via_partition_root set to true does not result in the table's existing contents being replicated.

COPY ... FROM commands are published as INSERT operations.

DDL operations are not published.

Examples

Create a publication that publishes all changes in two tables:

CREATE PUBLICATION mypublication FOR TABLE users, departments;

Create a publication that publishes all changes in all tables:

CREATE PUBLICATION alltables FOR ALL TABLES;

Create a publication that only publishes INSERT operations in one table:

CREATE PUBLICATION insert_only FOR TABLE mydata
    WITH (publish = 'insert');

Compatibility

CREATE PUBLICATION is a LightDB extension.