NAME

       pg_waldump - display a human-readable rendering of the write-ahead log of a PostgreSQL
       database cluster

SYNOPSIS

       pg_waldump [option...] [startseg [endseg]]

DESCRIPTION

       pg_waldump displays the write-ahead log (WAL) and is mainly useful for debugging or
       educational purposes.

       This utility can only be run by the user who installed the server, because it requires
       read-only access to the data directory.

OPTIONS

       The following command-line options control the location and format of the output:

       startseg
           Start reading at the specified log segment file. This implicitly determines the path
           in which files will be searched for, and the timeline to use.

       endseg
           Stop after reading the specified log segment file.

       -b
       --bkp-details
           Output detailed information about backup blocks.

       -B block
       --block=block
           Only display records that modify the given block. The relation must also be provided
           with --relation or -R.

       -e end
       --end=end
           Stop reading at the specified WAL location, instead of reading to the end of the log
           stream.

       -f
       --follow
           After reaching the end of valid WAL, keep polling once per second for new WAL to
           appear.

       -F fork
       --fork=fork
           If provided, only display records that modify blocks in the given fork. The valid
           values are main for the main fork, fsm for the free space map, vm for the visibility
           map, and init for the init fork.

       -n limit
       --limit=limit
           Display the specified number of records, then stop.

       -p path
       --path=path
           Specifies a directory to search for log segment files or a directory with a pg_wal
           subdirectory that contains such files. The default is to search in the current
           directory, the pg_wal subdirectory of the current directory, and the pg_wal
           subdirectory of PGDATA.

       -q
       --quiet
           Do not print any output, except for errors. This option can be useful when you want to
           know whether a range of WAL records can be successfully parsed but don't care about
           the record contents.

       -r rmgr
       --rmgr=rmgr
           Only display records generated by the specified resource manager. You can specify the
           option multiple times to select multiple resource managers. If list is passed as name,
           print a list of valid resource manager names, and exit.

           Extensions may define custom resource managers, but pg_waldump does not load the
           extension module and therefore does not recognize custom resource managers by name.
           Instead, you can specify the custom resource managers as custom### where "###" is the
           three-digit resource manager ID. Names of this form will always be considered valid.

       -R tblspc/db/rel
       --relation=tblspc/db/rel
           Only display records that modify blocks in the given relation. The relation is
           specified with tablespace OID, database OID, and relfilenode separated by slashes, for
           example 1234/12345/12345. This is the same format used for relations in the program's
           output.

       -s start
       --start=start
           WAL location at which to start reading. The default is to start reading the first
           valid log record found in the earliest file found.

       -t timeline
       --timeline=timeline
           Timeline from which to read log records. The default is to use the value in startseg,
           if that is specified; otherwise, the default is 1.

       -V
       --version
           Print the pg_waldump version and exit.

       -w
       --fullpage
           Only display records that include full page images.

       -x xid
       --xid=xid
           Only display records marked with the given transaction ID.

       -z
       --stats[=record]
           Display summary statistics (number and size of records and full-page images) instead
           of individual records. Optionally generate statistics per-record instead of per-rmgr.

           If pg_waldump is terminated by signal SIGINT (Control+C), the summary of the
           statistics computed is displayed up to the termination point. This operation is not
           supported on Windows.

       -?
       --help
           Show help about pg_waldump command line arguments, and exit.

ENVIRONMENT

       PGDATA
           Data directory; see also the -p option.

       PG_COLOR
           Specifies whether to use color in diagnostic messages. Possible values are always,
           auto and never.

NOTES

       Can give wrong results when the server is running.

       Only the specified timeline is displayed (or the default, if none is specified). Records
       in other timelines are ignored.

       pg_waldump cannot read WAL files with suffix .partial. If those files need to be read,
       .partial suffix needs to be removed from the file name.

SEE ALSO

       Section 30.6