lt_archivecleanup — clean up LightDB WAL archive files
lt_archivecleanup [option...] archivelocation oldestkeptwalfile
lt_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).
lt_archivecleanup can also be used as a standalone program to
clean WAL file archives.
To configure a standby
server to use lt_archivecleanup, put this into its
lightdb.conf configuration file:
archive_cleanup_command = 'lt_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 .partial or .backup
file name, then only the file prefix will be used as the
oldestkeptwalfile. This treatment of .backup
file name 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:
lt_archivecleanup -d archive 000000010000003700000010.00000020.backup lt_archivecleanup: keep WAL file "archive/000000010000003700000010" and later lt_archivecleanup: removing file "archive/00000001000000370000000F" lt_archivecleanup: removing file "archive/00000001000000370000000E"
lt_archivecleanup assumes that
archivelocation is a directory readable and writable by the
server-owning user.
lt_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--versionPrint the lt_archivecleanup version and exit.
-x extension
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.
-?--helpShow help about lt_archivecleanup command line arguments, and exit.
The environment variable LT_COLOR specifies whether to use
color in diagnostic messages. Possible values are
always, auto and
never.
lt_archivecleanup is designed to work with LightDB 8.0 and later when used as a standalone utility, or with LightDB 9.0 and later when used as an archive cleanup command.
lt_archivecleanup is written in C and has an easy-to-modify source code, with specifically designated sections to modify for your own needs
On Linux or Unix systems, you might use:
archive_cleanup_command = 'lt_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