adminpack provides a number of support functions which pgAdmin and other administration and management tools can use to provide additional functionality, such as remote management of server log files. Use of all these functions is only allowed to the superuser by default but may be allowed to other users by using the GRANT command.
The functions shown in Table F.1 provide write access to files on the machine hosting the server. (See also the functions in Table 9.88, which provide read-only access.) Only files within the database cluster directory can be accessed, unless the user is a superuser or given one of the pg_read_server_files, or pg_write_server_files roles, as appropriate for the function, but either a relative or absolute path is allowable.
Table F.1. adminpack Functions
| Name | Return Type | Description |
|---|---|---|
pg_catalog.pg_file_write(filename text, data text, append boolean) |
bigint |
Write, or append to, a text file |
pg_catalog.pg_file_rename(oldname text, newname text [, archivename text]) |
boolean |
Rename a file |
pg_catalog.pg_file_unlink(filename text) |
boolean |
Remove a file |
pg_catalog.pg_logdir_ls() |
setof record |
List the log files in the log_directory directory |
pg_file_write writes the specified data into the file named by filename. If append is false, the file must not already exist. If append is true, the file can already exist, and will be appended to if so. Returns the number of bytes written.
pg_file_rename renames a file. If archivename is omitted or NULL, it simply renames oldname to newname (which must not already exist). If archivename is provided, it first renames newname to archivename (which must not already exist), and then renames oldname to newname. In event of failure of the second rename step, it will try to rename archivename back to newname before reporting the error. Returns true on success, false if the source file(s) are not present or not writable; other cases throw errors.
pg_file_unlink removes the specified file. Returns true on success, false if the specified file is not present or the unlink() call fails; other cases throw errors.
pg_logdir_ls returns the start timestamps and path names of all the log files in the log_directory directory. The log_filename parameter must have its default setting (postgresql-%Y-%m-%d_%H%M%S.log) to use this function.