pg_waldump(1)

1PG_WALDUMP(1)            PostgreSQL 15.4 Documentation           PG_WALDUMP(1)
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NAME

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

10       pg_waldump [option...] [startseg [endseg]]
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DESCRIPTION

13       pg_waldump displays the write-ahead log (WAL) and is mainly useful for
14       debugging or educational purposes.
15
16       This utility can only be run by the user who installed the server,
17       because it requires read-only access to the data directory.
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OPTIONS

20       The following command-line options control the location and format of
21       the output:
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23       startseg
24           Start reading at the specified log segment file. This implicitly
25           determines the path in which files will be searched for, and the
26           timeline to use.
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28       endseg
29           Stop after reading the specified log segment file.
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31       -b
32       --bkp-details
33           Output detailed information about backup blocks.
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35       -B block
36       --block=block
37           Only display records that modify the given block. The relation must
38           also be provided with --relation or -R.
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40       -e end
41       --end=end
42           Stop reading at the specified WAL location, instead of reading to
43           the end of the log stream.
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45       -f
46       --follow
47           After reaching the end of valid WAL, keep polling once per second
48           for new WAL to appear.
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50       -F fork
51       --fork=fork
52           If provided, only display records that modify blocks in the given
53           fork. The valid values are main for the main fork, fsm for the free
54           space map, vm for the visibility map, and init for the init fork.
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56       -n limit
57       --limit=limit
58           Display the specified number of records, then stop.
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60       -p path
61       --path=path
62           Specifies a directory to search for log segment files or a
63           directory with a pg_wal subdirectory that contains such files. The
64           default is to search in the current directory, the pg_wal
65           subdirectory of the current directory, and the pg_wal subdirectory
66           of PGDATA.
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68       -q
69       --quiet
70           Do not print any output, except for errors. This option can be
71           useful when you want to know whether a range of WAL records can be
72           successfully parsed but don't care about the record contents.
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74       -r rmgr
75       --rmgr=rmgr
76           Only display records generated by the specified resource manager.
77           You can specify the option multiple times to select multiple
78           resource managers. If list is passed as name, print a list of valid
79           resource manager names, and exit.
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81           Extensions may define custom resource managers, but pg_waldump does
82           not load the extension module and therefore does not recognize
83           custom resource managers by name. Instead, you can specify the
84           custom resource managers as custom### where "###" is the
85           three-digit resource manager ID. Names of this form will always be
86           considered valid.
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88       -R tblspc/db/rel
89       --relation=tblspc/db/rel
90           Only display records that modify blocks in the given relation. The
91           relation is specified with tablespace OID, database OID, and
92           relfilenode separated by slashes, for example 1234/12345/12345.
93           This is the same format used for relations in the program's output.
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95       -s start
96       --start=start
97           WAL location at which to start reading. The default is to start
98           reading the first valid log record found in the earliest file
99           found.
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101       -t timeline
102       --timeline=timeline
103           Timeline from which to read log records. The default is to use the
104           value in startseg, if that is specified; otherwise, the default is
105           1.
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107       -V
108       --version
109           Print the pg_waldump version and exit.
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111       -w
112       --fullpage
113           Only display records that include full page images.
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115       -x xid
116       --xid=xid
117           Only display records marked with the given transaction ID.
118
119       -z
120       --stats[=record]
121           Display summary statistics (number and size of records and
122           full-page images) instead of individual records. Optionally
123           generate statistics per-record instead of per-rmgr.
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125           If pg_waldump is terminated by signal SIGINT (Control+C), the
126           summary of the statistics computed is displayed up to the
127           termination point. This operation is not supported on Windows.
128
129       -?
130       --help
131           Show help about pg_waldump command line arguments, and exit.
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ENVIRONMENT

134       PGDATA
135           Data directory; see also the -p option.
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137       PG_COLOR
138           Specifies whether to use color in diagnostic messages. Possible
139           values are always, auto and never.
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NOTES

142       Can give wrong results when the server is running.
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144       Only the specified timeline is displayed (or the default, if none is
145       specified). Records in other timelines are ignored.
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147       pg_waldump cannot read WAL files with suffix .partial. If those files
148       need to be read, .partial suffix needs to be removed from the file
149       name.
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NAME

SYNOPSIS

DESCRIPTION

OPTIONS

ENVIRONMENT

NOTES

SEE ALSO