The lo_compat_privileges GUC restores large-object security behavior to the insecure state of PostgreSQL 8.4, where objects lacked owners and were readable by any connected role. Prior to this, version 9.0 introduced owner-based access control lists (ACLs) for large objects. Enabling this setting effectively disables those modern protections.
- Enabling lo_compat_privileges removes large object ownership and ACLs entirely.
- Any authenticated role can read, overwrite, or delete large objects in the database.
- This reverts security to the pre-9.0 era, posing significant data integrity risks.
- Review configuration files to ensure this GUC is not accidentally enabled in production.