Postgres Plus Advanced Server Oracle Compatibility Developer's Guide :
Postgres Plus Advanced Server Oracle Compatibility Developer's Guide
7 Built-In Packages
This chapter describes the built-in packages that are provided with Postgres Plus Advanced Server. For certain packages, non-superusers must be explicitly granted the EXECUTE privilege on the package before using any of the package’s functions or procedures. For most of the built-in packages, EXECUTE privilege has been granted to PUBLIC by default. See the GRANT command for granting privileges.
All built-in packages are owned by the special sys user which must be specified when granting or revoking privileges on built-in packages:
GRANT EXECUTE ON PACKAGE SYS.UTL_FILE TO john;