1PG_WALDUMP(1) PostgreSQL 13.4 Documentation PG_WALDUMP(1)
2
6 pg_waldump - display a human-readable rendering of the write-ahead log
7 of a PostgreSQL database cluster
8
10 pg_waldump [option...] [startseg [endseg]]
11
13 pg_waldump displays the write-ahead log (WAL) and is mainly useful for
14 debugging or educational purposes.
15 This utility can only be run by the user who installed the server,
17 because it requires read-only access to the data directory.
18
20 The following command-line options control the location and format of
21 the output:
22 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.
27 endseg
29 Stop after reading the specified log segment file.
30 -b
32 --bkp-details
33 Output detailed information about backup blocks.
34 -e end
36 --end=end
37 Stop reading at the specified WAL location, instead of reading to
38 the end of the log stream.
39 -f
41 --follow
42 After reaching the end of valid WAL, keep polling once per second
43 for new WAL to appear.
44 -n limit
46 --limit=limit
47 Display the specified number of records, then stop.
48 -p path
50 --path=path
51 Specifies a directory to search for log segment files or a
52 directory with a pg_wal subdirectory that contains such files. The
53 default is to search in the current directory, the pg_wal
54 subdirectory of the current directory, and the pg_wal subdirectory
55 of PGDATA.
56 -q
58 --quiet
59 Do not print any output, except for errors. This option can be
60 useful when you want to know whether a range of WAL records can be
61 successfully parsed but don't care about the record contents.
62 -r rmgr
64 --rmgr=rmgr
65 Only display records generated by the specified resource manager.
66 If list is passed as name, print a list of valid resource manager
67 names, and exit.
68 -s start
70 --start=start
71 WAL location at which to start reading. The default is to start
72 reading the first valid log record found in the earliest file
73 found.
74 -t timeline
76 --timeline=timeline
77 Timeline from which to read log records. The default is to use the
78 value in startseg, if that is specified; otherwise, the default is
79 1.
80 -V
82 --version
83 Print the pg_waldump version and exit.
84 -x xid
86 --xid=xid
87 Only display records marked with the given transaction ID.
88 -z
90 --stats[=record]
91 Display summary statistics (number and size of records and
92 full-page images) instead of individual records. Optionally
93 generate statistics per-record instead of per-rmgr.
94 -?
96 --help
97 Show help about pg_waldump command line arguments, and exit.
98
100 PGDATA
101 Data directory; see also the -p option.
102 PG_COLOR
104 Specifies whether to use color in diagnostic messages. Possible
105 values are always, auto and never.
106
108 Can give wrong results when the server is running.
109 Only the specified timeline is displayed (or the default, if none is
111 specified). Records in other timelines are ignored.
112 pg_waldump cannot read WAL files with suffix .partial. If those files
114 need to be read, .partial suffix needs to be removed from the file
115 name.
116
118 Section 29.5
119PostgreSQL 13.4 2021 PG_WALDUMP(1)