# File Locations

> Complete dossiers for 7 core PostgreSQL settings in File Locations.
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Dossier URLs remain flat; this category exists only to organize browsing and the sidebar.

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Section pages:

- [config_file](/parameters/config-file/): config_file — Sets the server's main configuration file. Observed in PG9.0–19 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.
- [data_directory](/parameters/data-directory/): data_directory — Sets the server's data directory. Observed in PG9.0–19 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.
- [extension_destdir](/parameters/extension-destdir/): extension_destdir is a Debian/PGDG downstream staging-prefix GUC observed in the packaged PostgreSQL 9.5–17 images. It was never an upstream PostgreSQL parameter and disappears from the measured packages at PostgreSQL 18.
- [external_pid_file](/parameters/external-pid-file/): external_pid_file — Writes the postmaster PID to the specified file. Observed in PG9.0–19 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.
- [hba_file](/parameters/hba-file/): hba_file — Sets the server's "hba" configuration file. Observed in PG9.0–19 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.
- [hosts_file](/parameters/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.
- [ident_file](/parameters/ident-file/): ident_file — Sets the server's "ident" configuration file. Observed in PG9.0–19 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.