ssl

Definition PG 18 manual

Enables SSL connections. This parameter can only be set in the postgresql.conf file or on the server command line. The default is off.

How it works

ssl enables SSL connections. Turning it on makes TLS listeners available when certificate and key material are valid; pg_hba.conf hostssl rules are what require TLS for selected clients.

ssl is a SIGHUP-context setting: a configuration reload activates the new server value without a restart; subsequent operations that consult it use the refreshed value. Existing TLS sessions are not renegotiated.

It participates in the TLS context used for new handshakes. ssl enables transport, pg_hba.conf decides which connection classes require it, and the certificate, key, CA, revocation, protocol, and cipher settings must form one valid policy.

Operational considerations

Editing ssl without reloading configuration and verifying the effective value and subsequent behavior.

Updating only one TLS file or policy knob and leaving an invalid chain, unreadable key, or incompatible protocol set.

Assuming a reload renegotiates existing sessions; TLS policy changes affect new handshakes.

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

Workload guidance

OLAP: Use the same TLS floor for analytical traffic; benchmark only after correctness because bulk transfer may expose CPU cost but is not a reason to accept obsolete protocols.

OLTP: Treat ssl as transport-security policy rather than a performance knob. Follow the organization's TLS baseline and test certificate rotation, reload, and every client class.

SMALL: Keep ssl simple and secure, using managed certificates and library defaults reviewed for the installed OpenSSL version. Rehearse renewal before expiry.