pg_combinebackup — reconstruct a full backup from an incremental backup and dependent backups
pg_combinebackup
[option
...] [backup_directory
...]
pg_combinebackup is used to reconstruct a synthetic full backup from an incremental backup and the earlier backups upon which it depends.
Specify all of the required backups on the command line from oldest to newest.
That is, the first backup directory should be the path to the full backup, and
the last should be the path to the final incremental backup
that you wish to restore. The reconstructed backup will be written to the
output directory specified by the -o
option.
Although pg_combinebackup will attempt to verify that the backups you specify form a legal backup chain from which a correct full backup can be reconstructed, it is not designed to help you keep track of which backups depend on which other backups. If you remove the one or more of the previous backups upon which your incremental backup relies, you will not be able to restore it.
Since the output of pg_combinebackup is a synthetic full backup, it can be used as an input to a future invocation of pg_combinebackup. The synthetic full backup would be specified on the command line in lieu of the chain of backups from which it was reconstructed.
-d
--debug
Print lots of debug logging output on stderr
.
-n
--dry-run
The -n
/--dry-run
option instructs
pg_combinebackup
to figure out what would be done
without actually creating the target directory or any output files.
It is particularly useful in combination with --debug
.
-N
--no-sync
By default, pg_combinebackup
will wait for all files
to be written safely to disk. This option causes
pg_combinebackup
to return without waiting, which is
faster, but means that a subsequent operating system crash can leave
the output backup corrupt. Generally, this option is useful for testing
but should not be used when creating a production installation.
-o outputdir
--output=outputdir
Specifies the output directory to which the synthetic full backup should be written. Currently, this argument is required.
-T olddir
=newdir
--tablespace-mapping=olddir
=newdir
Relocates the tablespace in directory olddir
to newdir
during the backup.
olddir
is the absolute path of the tablespace
as it exists in the first backup specified on the command line,
and newdir
is the absolute path to use for the
tablespace in the reconstructed backup. If either path needs to contain
an equal sign (=
), precede that with a backslash.
This option can be specified multiple times for multiple tablespaces.
--manifest-checksums=algorithm
Like pg_basebackup,
pg_combinebackup writes a backup manifest
in the output directory. This option specifies the checksum algorithm
that should be applied to each file included in the backup manifest.
Currently, the available algorithms are NONE
,
CRC32C
, SHA224
,
SHA256
, SHA384
,
and SHA512
. The default is CRC32C
.
--no-manifest
Disables generation of a backup manifest. If this option is not specified, a backup manifest for the reconstructed backup will be written to the output directory.
--sync-method=method
When set to fsync
, which is the default,
pg_combinebackup
will recursively open and synchronize
all files in the backup directory. When the plain format is used, the
search for files will follow symbolic links for the WAL directory and
each configured tablespace.
On Linux, syncfs
may be used instead to ask the
operating system to synchronize the whole file system that contains the
backup directory. When the plain format is used,
pg_combinebackup
will also synchronize the file systems
that contain the WAL files and each tablespace. See
Appendix O for more information about using
syncfs()
.
This option has no effect when --no-sync
is used.
-V
--version
Prints the pg_combinebackup version and exits.
-?
--help
Shows help about pg_combinebackup command line arguments, and exits.
This utility, like most other PostgreSQL utilities, uses the environment variables supported by libpq (see Section 33.15).
The environment variable PG_COLOR
specifies whether to use
color in diagnostic messages. Possible values are
always
, auto
and
never
.