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PG_WALDUMP(1) PostgreSQL 12.3 Documentation PG_WALDUMP(1)
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.
-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.
-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.
-r rmgr
--rmgr=rmgr
Only display records generated by the specified resource manager. If list is passed as
name, print a list of valid resource manager names, and exit.
-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.
-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.
-?
--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 29.5
PostgreSQL 12.3 2020 PG_WALDUMP(1)
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