The role used for the replication connection must have
the REPLICATION attribute (or be a superuser). If the
role lacks SUPERUSER and BYPASSRLS,
publisher row security policies can execute. If the role does not trust
all table owners, include options=-crow_security=off in
the connection string; if a table owner then adds a row security policy,
that setting will cause replication to halt rather than execute the policy.
Access for the role must be configured in pg_hba.conf
and it must have the LOGIN attribute.
To create a publication, the user must have the CREATE
privilege in the database.
To add tables to a publication, the user must have ownership rights on the table. To add all tables in schema to a publication, the user must be a superuser. To create a publication that publishes all tables or all tables in schema automatically, the user must be a superuser.
To replicate data, the role used for the replication connection must have
the USAGE privilege on the publication. In such a case,
the subscription role needs neither the SELECT
privileges on the replicated tables nor the USAGE
privilege on the containing schemas.
The USAGE privilege on publication is only checked if
the publication_security
configuration parameter is set. The default is off. It
should only be set to on if all the subscribers are
on PostgreSQL server version which supports the
USAGE privilege on publications. The older versions do
not send the publication names for the initial table synchronization, so
they would fail to receive the data.
There are currently no privileges on publications. Any subscription (that is able to connect) can access any publication. Thus, if you intend to hide some information from particular subscribers, such as by using row filters or column lists, or by not adding the whole table to the publication, be aware that other publications in the same database could expose the same information. Publication privileges might be added to PostgreSQL in the future to allow for finer-grained access control.
To create a subscription, the user must have the privileges of
the pg_create_subscription role, as well as
CREATE privileges on the database.
The subscription apply process will, at a session level, run with the
privileges of the subscription owner. However, when performing an insert,
update, delete, or truncate operation on a particular table, it will switch
roles to the table owner and perform the operation with the table owner's
privileges. This means that the subscription owner needs to be able to
SET ROLE to each role that owns a replicated table.
If the subscription has been configured with
run_as_owner = true, then no user switching will
occur. Instead, all operations will be performed with the permissions
of the subscription owner. In this case, the subscription owner only
needs privileges to SELECT, INSERT,
UPDATE, and DELETE from the
target table, and does not need privileges to SET ROLE
to the table owner. However, this also means that any user who owns
a table into which replication is happening can execute arbitrary code with
the privileges of the subscription owner. For example, they could do this
by simply attaching a trigger to one of the tables which they own.
Because it is usually undesirable to allow one role to freely assume
the privileges of another, this option should be avoided unless user
security within the database is of no concern.
On the publisher, privileges are only checked once at the start of a replication connection and are not re-checked as each change record is read.
On the subscriber, the subscription owner's privileges are re-checked for each transaction when applied. If a worker is in the process of applying a transaction when the ownership of the subscription is changed by a concurrent transaction, the application of the current transaction will continue under the old owner's privileges.