pg_archivecleanup
Description
pg_archivecleanup is designed to be used as an archive_cleanup_command to clean up WAL file archives when running as a standby server (see Section 25.2). pg_archivecleanup can also be used as a standalone program to clean WAL file archives.
To configure a standby server to use pg_archivecleanup, put this into its recovery.conf configuration file:
archive_cleanup_command = 'pg_archivecleanup archivelocation %r'
where archivelocation is the directory from which WAL segment files should be removed.
When used within archive_cleanup_command, all WAL files logically preceding the value of the %r argument will be removed from archivelocation. This minimizes the number of files that need to be retained, while preserving crash-restart capability. Use of this parameter is appropriate if the archivelocation is a transient staging area for this particular standby server, but not when the archivelocation is intended as a long-term WAL archive area, or when multiple standby servers are recovering from the same archive location.
When used as a standalone program all WAL files logically preceding the oldestkeptwalfile will be removed from archivelocation. In this mode, if you specify a .backup file name, then only the file prefix will be used as the oldestkeptwalfile. This allows you to remove all WAL files archived prior to a specific base backup without error. For example, the following example will remove all files older than WAL file name 000000010000003700000010:
pg_archivecleanup -d archive 000000010000003700000010.00000020.backup pg_archivecleanup: keep WAL file "archive/000000010000003700000010" and later pg_archivecleanup: removing file "archive/00000001000000370000000F" pg_archivecleanup: removing file "archive/00000001000000370000000E"
pg_archivecleanup assumes that archivelocation is a directory readable and writable by the server-owning user.
Options
pg_archivecleanup accepts the following command-line arguments:
- -d
Print lots of debug logging output on stderr.
- -n
Print the names of the files that would have been removed on stdout (performs a dry run).
- -V
--version Print the pg_archivecleanup version and exit.
- -x extension
When using the program as a standalone utility, provide an extension that will be stripped from all file names before deciding if they should be deleted. This is typically useful for cleaning up archives that have been compressed during storage, and therefore have had an extension added by the compression program. For example: -x .gz.
Note that the .backup file name passed to the program should not include the extension.
- -?
--help Show help about pg_archivecleanup command line arguments, and exit.
Notes
pg_archivecleanup is designed to work with PostgreSQL 8.0 and later when used as a standalone utility, or with PostgreSQL 9.0 and later when used as an archive cleanup command.
pg_archivecleanup is written in C and has an easy-to-modify source code, with specifically designated sections to modify for your own needs
Examples
On Linux or Unix systems, you might use:
archive_cleanup_command = 'pg_archivecleanup -d /mnt/standby/archive %r 2>>cleanup.log'
where the archive directory is physically located on the standby server, so that the archive_command is accessing it across NFS, but the files are local to the standby. This will:
produce debugging output in cleanup.log
remove no-longer-needed files from the archive directory