bonjour

Definition PG 18 manual

Enables advertising the server's existence via Bonjour. The default is off. This parameter can only be set at server start.

How it works

bonjour enables advertising the server via Bonjour. It publishes a discoverable service through mDNS only on builds and platforms with Bonjour support; it does not open a listener or alter pg_hba.conf.

bonjour is a POSTMASTER-context setting: PostgreSQL reads it during server startup, and a configuration reload or session SET cannot activate a new value.

Bonjour advertisement depends on platform support and publishes the listener as metadata; listen_addresses, port, pg_hba.conf, TLS, and firewalls still define actual reachability and trust.

Operational considerations

Expecting a reload or SET to activate bonjour, although it requires a controlled server restart.

Treating an mDNS advertisement as an access-control, authentication, or high-availability mechanism.

Publishing an unexpected service name or endpoint on an untrusted broadcast domain.

Changing bonjour globally without a rollback plan and a client or operational compatibility test.

Workload guidance

OLAP: Analytical workload shape does not justify different bonjour behavior; use the same reviewed discovery policy and stable service identity.

OLTP: Enable bonjour only when clients deliberately use Bonjour/mDNS on a trusted local network. Treat it as discovery metadata, never as authentication or a highly available service registry.

SMALL: Leave bonjour off or empty unless local zero-configuration discovery is an explicit requirement; it does not improve database capacity.