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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.
pg_archivecleanup features include:
Written in C, so very portable and easy to install
Easy-to-modify source code, with specifically designated sections to modify for your own needs
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.
The full syntax of pg_archivecleanup's command line is
pg_archivecleanup [ option ... ] archivelocation restartwalfile
When used as a standalone program all WAL files logically preceding the restartwalfile will be removed archivelocation. In this mode, if you specify a .backup file name, then only the file prefix will be used as the restartwalfile. 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.
pg_archivecleanup accepts the following command-line arguments:
Print lots of debug logging output on stderr.
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
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.
Simon Riggs <simon@2ndquadrant.com>