config_file_error syntax error in file “…” line N, near token “…” — F0000

Symptoms

PostgreSQL could not parse a configuration file (such as postgresql.conf or pg_hba.conf) because of a syntax problem near the reported token. It raises SQLSTATE F0000 (config_file_error).

• The message names the file, line number, and offending token.
• Often appears at startup or after a reload.
• A bad line can prevent the server from starting.

What the server log shows

FATAL:  syntax error in file "/etc/postgresql/18/main/postgresql.conf" line 142, near token "on"

Why PostgreSQL raises this — what the manual says

Section 19.1.2 Parameter Interaction via the Configuration File:

“One parameter is specified per line.”

On startup or reload, PostgreSQL parses configuration files line by line. A malformed entry (bad quoting, missing value, stray token) stops parsing and is reported as F0000, with the location to fix.

Common causes

• A missing or unbalanced quote/value in a parameter line.
• An invalid keyword or stray character.
• A malformed pg_hba.conf/postgresql.conf edit.

How to fix it

1. Open the named file at the reported line and fix the syntax.
2. Quote string values correctly and ensure each setting has a value.
3. Validate before reload (e.g. postgres -C checks or a config linter), then SELECT pg_reload_conf();.

Related & next steps

• SQLSTATE F0000 — Config File Error (full reference)
• Message: lock file already exists
• Glossary: postgresql.conf

Reference: PostgreSQL 18 Section 20.1 “Setting Parameters”.