pg_waldump — display a human-readable rendering of the write-ahead log of a PostgreSQL database cluster
pg_waldump [option...] [startseg [endseg]]
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.
The following command-line options control the location and format of the output:
startsegStart reading at the specified log segment file. This implicitly determines the path in which files will be searched for, and the timeline to use.
endsegStop after reading the specified log segment file.
-b--bkp-detailsOutput detailed information about backup blocks.
-e end--end=endStop reading at the specified WAL location, instead of reading to the end of the log stream.
-f--followAfter reaching the end of valid WAL, keep polling once per second for new WAL to appear.
-n limit--limit=limitDisplay 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=startWAL 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--versionPrint the pg_waldump version and exit.
-x xid--xid=xidOnly 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.
-?--helpShow help about pg_waldump command line arguments, and exit.
PGDATA
Data directory; see also the -p option.
PG_COLOR
Specifies whether to use color in diagnostics messages. Possible values
are always, auto,
never.
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.