hosts_file

hosts_file — Sets the server’s “hosts” configuration file. Observed in PG19 Beta 3; its last measured boot default is not set in PG19 Beta 3, with postmaster context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.

Note

Fact — official short description: “Sets the server’s “hosts” configuration file.”

Identity

Type , Valuestring: Upstream pg_settings type
Context , Valuepostmaster: Requires a server restart
Unit , Value—: Raw unit
Range , Value—: Raw limits in the last observed version
Enum values , Value—: — for non-enum types
Category , ValueFile Locations: Upstream classification
Latest boot value , Value—: not set

Lifecycle

Fact	Value
First observed	PG19 Beta 3
Present in	PG19 Beta 3
Removed in	No
Introduction commit	`4f433025f666` — ssl: Serverside SNI support for libpq
Commit date	2026-03-18
Discussion	thread 1

Default history

Measured PG9.0–19 Beta 3 boot defaults
Versions	Raw `boot_val`	Unit	Human value
PG19 Beta 3	—	—	not set

How it works

PostgreSQL describes hosts_file as follows: “Sets the server’s “hosts” configuration file.” The value is fixed when the server starts, so changing it requires a controlled restart. The atlas measures it in PG19 Beta 3; boot_val is the compiled or initialized baseline, not proof of a running cluster’s effective setting.

The path identifies pg_hosts.conf, the server-side SNI mapping file introduced in PostgreSQL 19. When ssl_sni is enabled, hostname, /no_sni/, and wildcard entries select certificate, key, optional CA, and optional passphrase commands; an empty or missing file falls back to the ordinary postgresql.conf TLS files.

Read it together with ssl_sni, ssl_cert_file, ssl_key_file, ssl_ca_file. Check SHOW and pg_settings on the target server, verify the source and pending_restart fields, and compare workload, logs, and resource metrics before and after any change.

Tuning advice

Tip

Advice. These are workload-specific starting points and must be validated with measurements.

Workload	Guidance
OLTP	Roll out through staged clients, validate certificate selection and expiry warnings, and monitor authentication failures. Keep a tested fallback and treat file permissions and secret rotation as part of the same change.
OLAP	Apply the same security policy to batch drivers and long-lived ETL connections. Test clients that omit SNI, credential-expiry automation, reload behavior, and certificate-chain compatibility.
Small nodes	Prefer a simple, documented TLS and credential policy. Do not enable multi-certificate routing without a test for every hostname and fallback path, and never weaken verification to hide configuration mistakes.

Pigsty

Values use the fixed 8-vCPU, 32-GiB, 100-GiB SSD fixture and render the current Pigsty templates for PG19 Beta 3; this does not assert current Pigsty support for that historical or beta release.

Template	Effective value	Versus upstream boot	Source expression
OLTP	Unmodified	—	—
OLAP	Unmodified	—	—
CRIT	Unmodified	—	—
TINY	Unmodified	—	—

Caution

Advice — pending human review. Fact from the current Pigsty template projection: OLTP: PG19 Beta 3 unmodified; OLAP: PG19 Beta 3 unmodified; CRIT: PG19 Beta 3 unmodified; TINY: PG19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

Common pitfalls

Treating the measured boot_val for hosts_file as proof of the effective value on an initialized or managed cluster.
Applying a change as though it were immediate while pg_settings reports postmaster context.
Changing this setting in isolation without checking the linked limits, observability, and rollback path.
Depending on beta behavior in production without retesting the PostgreSQL 19 final release.

ssl_sni · ssl_cert_file · ssl_key_file · ssl_ca_file · hba_file