pg_walsummary(1) PostgreSQL 17.4 Documentation pg_walsummary(1)
NAME
pg_walsummary - print contents of WAL summary files
SYNOPSIS
pg_walsummary [option...] [file...]
DESCRIPTION
pg_walsummary is used to print the contents of WAL summary files. These
binary files are found with the pg_wal/summaries subdirectory of the
data directory, and can be converted to text using this tool. This is
not ordinarily necessary, since WAL summary files primarily exist to
support incremental backup, but it may be useful for debugging
purposes.
A WAL summary file is indexed by tablespace OID, relation OID, and
relation fork. For each relation fork, it stores the list of blocks
that were modified by WAL within the range summarized in the file. It
can also store a "limit block," which is 0 if the relation fork was
created or truncated within the relevant WAL range, and otherwise the
shortest length to which the relation fork was truncated. If the
relation fork was not created, deleted, or truncated within the
relevant WAL range, the limit block is undefined or infinite and will
not be printed by this tool.
OPTIONS
-i
--individual
By default, pg_walsummary prints one line of output for each range
of one or more consecutive modified blocks. This can make the
output a lot briefer, since a relation where all blocks from 0
through 999 were modified will produce only one line of output
rather than 1000 separate lines. This option requests a separate
line of output for every modified block.
-q
--quiet
Do not print any output, except for errors. This can be useful when
you want to know whether a WAL summary file can be successfully
parsed but don't care about the contents.
-V
--version
Display version information, then exit.
-?
--help
Shows help about pg_walsummary command line arguments, and exits.
ENVIRONMENT
The environment variable PG_COLOR specifies whether to use color in
diagnostic messages. Possible values are always, auto and never.
SEE ALSO
pg_basebackup(1), pg_combinebackup(1)
PostgreSQL 17.4 2025 pg_walsummary(1)
postgresql 17.4 - Generated Sat Mar 22 11:54:16 CDT 2025