unrecognized configuration parameter “…”

Symptoms

A configuration file referenced a parameter name PostgreSQL does not recognize. PostgreSQL raises SQLSTATE F0000 (config_file_error).

• An unknown parameter name in postgresql.conf (or included files).
• Common with typos or settings from a different version/extension.
• May block startup or a reload depending on context.

What the server log shows

ERROR:  unrecognized configuration parameter "shared_bufers"

Why PostgreSQL raises this — what the manual says

As Section 19.1.2 Parameter Interaction via the Configuration File explains:

A configuration file (postgresql.conf or an included file) listed a parameter name that PostgreSQL does not recognize; unrecognized names are reported when the configuration is loaded or reloaded.

PostgreSQL validates parameter names against known GUCs (and loaded extensions’ custom parameters). An unrecognized name (typo, removed setting, or an extension not loaded) can’t be applied, so it reports F0000.

Common causes

• A typo in the parameter name.
• A parameter removed/renamed in a newer version.
• An extension’s custom parameter set before the extension is loaded.

How to fix it

1. Correct the parameter name against the current documentation.
2. Remove obsolete settings after version upgrades.
3. Load the extension (or add it to shared_preload_libraries) before setting its parameters.

Related & next steps

• SQLSTATE F0000 — Config File Error (full reference)
• Message: parameter cannot be changed without restarting
• Glossary: GUC parameter

Reference: PostgreSQL 18 Section 20.1 “Setting Parameters”.