Parameters
Connections and Authentication
38 PostgreSQL 18.6 parameters. Each one has its own animation and explanation.
Authentication
authentication_timeout: Time a client gets to finish logging in before the server hangs up.gss_accept_delegation: Accept Kerberos credentials delegated by the client (PostgreSQL 16+).krb_caseins_users: Compare Kerberos/GSSAPI user names case-insensitively.krb_server_keyfile: Path of the Kerberos keytab the server uses for GSSAPI logins.md5_password_warnings: Warn when an MD5-hashed password is set (PostgreSQL 18).oauth_validator_libraries: Libraries that validate OAuth 2.0 bearer tokens (PostgreSQL 18).password_encryption: Hash algorithm used when a password is set: scram-sha-256 (default) or md5.scram_iterations: PBKDF2 iteration count stored in new SCRAM secrets (PostgreSQL 16+).
Connection Settings
bonjour: Advertise the server on the local network via Bonjour/zeroconf.bonjour_name: Service name used in the Bonjour advertisement (empty = computer name).listen_addresses: Which network interfaces accept TCP connections. Default: localhost only.max_connections: Total number of client connection slots. Every slot costs shared memory.port: TCP port (and socket file name) the server listens on. Default 5432.reserved_connections: Slots kept for roles granted pg_use_reserved_connections (PostgreSQL 16+).superuser_reserved_connections: Last few connection slots kept for superusers, for emergency access.unix_socket_directories: Directories where the local Unix-domain socket files are created.unix_socket_group: OS group that owns the Unix socket file. Use with mode 0770.unix_socket_permissions: File mode of the Unix socket (default 0777: any local user may try).
SSL
ssl: Turn on TLS (SSL) so clients can encrypt their connections.ssl_ca_file: Trusted CA certificates for verifying client certificates.ssl_cert_file: Server certificate file sent to clients during the TLS handshake.ssl_ciphers: Allowed cipher suites for TLS 1.2 and lower (OpenSSL syntax).ssl_crl_dir: Directory of CRLs, read on demand at connection time (PostgreSQL 14+).ssl_crl_file: Certificate revocation list file: client certificates that are no longer valid.ssl_dh_params_file: Custom Diffie-Hellman parameters for DHE cipher suites.ssl_groups: Key-exchange groups/curves for TLS (renamed from ssl_ecdh_curve in 18).ssl_key_file: Private key matching the server certificate. Must not be group/world readable.ssl_max_protocol_version: Newest TLS version allowed. Empty (default) = no upper limit.ssl_min_protocol_version: Oldest TLS version accepted. Default TLSv1.2.ssl_passphrase_command: Command that prints the passphrase for an encrypted SSL private key.ssl_passphrase_command_supports_reload: Also run ssl_passphrase_command on reload, so certificates can be rotated.ssl_prefer_server_ciphers: Use the server's cipher order instead of the client's. Default on.ssl_tls13_ciphers: Allowed cipher suites for TLS 1.3 connections (PostgreSQL 18).
TCP Settings
client_connection_check_interval: How often a running query checks that its client is still connected (0 = off).tcp_keepalives_count: Unanswered keepalive probes before the connection is declared dead (0 = OS default).tcp_keepalives_idle: Idle time before the OS sends the first TCP keepalive probe (0 = OS default).tcp_keepalives_interval: Seconds between unanswered keepalive probes (0 = OS default).tcp_user_timeout: Max time sent data may stay unacknowledged before TCP drops the link (0 = OS default).