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PG_RECEIVEWAL(1)                   PostgreSQL 14.23 Documentation                   PG_RECEIVEWAL(1)



NAME
       pg_receivewal - stream write-ahead logs from a PostgreSQL server

SYNOPSIS
       pg_receivewal [option...]

DESCRIPTION
       pg_receivewal is used to stream the write-ahead log from a running PostgreSQL cluster. The
       write-ahead log is streamed using the streaming replication protocol, and is written to a
       local directory of files. This directory can be used as the archive location for doing a
       restore using point-in-time recovery (see Section 26.3).

       pg_receivewal streams the write-ahead log in real time as it's being generated on the server,
       and does not wait for segments to complete like archive_command does. For this reason, it is
       not necessary to set archive_timeout when using pg_receivewal.

       Unlike the WAL receiver of a PostgreSQL standby server, pg_receivewal by default flushes WAL
       data only when a WAL file is closed. The option --synchronous must be specified to flush WAL
       data in real time. Since pg_receivewal does not apply WAL, you should not allow it to become
       a synchronous standby when synchronous_commit equals remote_apply. If it does, it will appear
       to be a standby that never catches up, and will cause transaction commits to block. To avoid
       this, you should either configure an appropriate value for synchronous_standby_names, or
       specify application_name for pg_receivewal that does not match it, or change the value of
       synchronous_commit to something other than remote_apply.

       The write-ahead log is streamed over a regular PostgreSQL connection and uses the replication
       protocol. The connection must be made with a user having REPLICATION permissions (see
       Section 22.2) or a superuser, and pg_hba.conf must permit the replication connection. The
       server must also be configured with max_wal_senders set high enough to leave at least one
       session available for the stream.

       The starting point of the write-ahead log streaming is calculated when pg_receivewal starts:

        1. First, scan the directory where the WAL segment files are written and find the newest
           completed segment file, using as the starting point the beginning of the next WAL segment
           file.

        2. If a starting point cannot be calculated with the previous method, the latest WAL flush
           location is used as reported by the server from an IDENTIFY_SYSTEM command.

       If the connection is lost, or if it cannot be initially established, with a non-fatal error,
       pg_receivewal will retry the connection indefinitely, and reestablish streaming as soon as
       possible. To avoid this behavior, use the -n parameter.

       In the absence of fatal errors, pg_receivewal will run until terminated by the SIGINT signal
       (Control+C).

OPTIONS
       -D directory
       --directory=directory
           Directory to write the output to.

           This parameter is required.

       -E lsn
       --endpos=lsn
           Automatically stop replication and exit with normal exit status 0 when receiving reaches
           the specified LSN.

           If there is a record with LSN exactly equal to lsn, the record will be processed.

       --if-not-exists
           Do not error out when --create-slot is specified and a slot with the specified name
           already exists.

       -n
       --no-loop
           Don't loop on connection errors. Instead, exit right away with an error.

       --no-sync
           This option causes pg_receivewal to not force WAL data to be flushed to disk. This is
           faster, but means that a subsequent operating system crash can leave the WAL segments
           corrupt. Generally, this option is useful for testing but should not be used when doing
           WAL archiving on a production deployment.

           This option is incompatible with --synchronous.

       -s interval
       --status-interval=interval
           Specifies the number of seconds between status packets sent back to the server. This
           allows for easier monitoring of the progress from server. A value of zero disables the
           periodic status updates completely, although an update will still be sent when requested
           by the server, to avoid timeout disconnect. The default value is 10 seconds.

       -S slotname
       --slot=slotname
           Require pg_receivewal to use an existing replication slot (see Section 27.2.6). When this
           option is used, pg_receivewal will report a flush position to the server, indicating when
           each segment has been synchronized to disk so that the server can remove that segment if
           it is not otherwise needed.

           When the replication client of pg_receivewal is configured on the server as a synchronous
           standby, then using a replication slot will report the flush position to the server, but
           only when a WAL file is closed. Therefore, that configuration will cause transactions on
           the primary to wait for a long time and effectively not work satisfactorily. The option
           --synchronous (see below) must be specified in addition to make this work correctly.

       --synchronous
           Flush the WAL data to disk immediately after it has been received. Also send a status
           packet back to the server immediately after flushing, regardless of --status-interval.

           This option should be specified if the replication client of pg_receivewal is configured
           on the server as a synchronous standby, to ensure that timely feedback is sent to the
           server.

       -v
       --verbose
           Enables verbose mode.

       -Z level
       --compress=level
           Enables gzip compression of write-ahead logs, and specifies the compression level (0
           through 9, 0 being no compression and 9 being best compression). The suffix .gz will
           automatically be added to all filenames.

       The following command-line options control the database connection parameters.

       -d connstr
       --dbname=connstr
           Specifies parameters used to connect to the server, as a connection string; these will
           override any conflicting command line options.

           The option is called --dbname for consistency with other client applications, but because
           pg_receivewal doesn't connect to any particular database in the cluster, database name in
           the connection string will be ignored.

       -h host
       --host=host
           Specifies the host name of the machine on which the server is running. If the value
           begins with a slash, it is used as the directory for the Unix domain socket. The default
           is taken from the PGHOST environment variable, if set, else a Unix domain socket
           connection is attempted.

       -p port
       --port=port
           Specifies the TCP port or local Unix domain socket file extension on which the server is
           listening for connections. Defaults to the PGPORT environment variable, if set, or a
           compiled-in default.

       -U username
       --username=username
           User name to connect as.

       -w
       --no-password
           Never issue a password prompt. If the server requires password authentication and a
           password is not available by other means such as a .pgpass file, the connection attempt
           will fail. This option can be useful in batch jobs and scripts where no user is present
           to enter a password.

       -W
       --password
           Force pg_receivewal to prompt for a password before connecting to a database.

           This option is never essential, since pg_receivewal will automatically prompt for a
           password if the server demands password authentication. However, pg_receivewal will waste
           a connection attempt finding out that the server wants a password. In some cases it is
           worth typing -W to avoid the extra connection attempt.

       pg_receivewal can perform one of the two following actions in order to control physical
       replication slots:

       --create-slot
           Create a new physical replication slot with the name specified in --slot, then exit.

       --drop-slot
           Drop the replication slot with the name specified in --slot, then exit.

       Other options are also available:

       -V
       --version
           Print the pg_receivewal version and exit.

       -?
       --help
           Show help about pg_receivewal command line arguments, and exit.

EXIT STATUS
       pg_receivewal will exit with status 0 when terminated by the SIGINT signal. (That is the
       normal way to end it. Hence it is not an error.) For fatal errors or other signals, the exit
       status will be nonzero.

ENVIRONMENT
       This utility, like most other PostgreSQL utilities, uses the environment variables supported
       by libpq (see Section 34.15).

       The environment variable PG_COLOR specifies whether to use color in diagnostic messages.
       Possible values are always, auto and never.

NOTES
       When using pg_receivewal instead of archive_command as the main WAL backup method, it is
       strongly recommended to use replication slots. Otherwise, the server is free to recycle or
       remove write-ahead log files before they are backed up, because it does not have any
       information, either from archive_command or the replication slots, about how far the WAL
       stream has been archived. Note, however, that a replication slot will fill up the server's
       disk space if the receiver does not keep up with fetching the WAL data.

       pg_receivewal will preserve group permissions on the received WAL files if group permissions
       are enabled on the source cluster.

EXAMPLES
       To stream the write-ahead log from the server at mydbserver and store it in the local
       directory /usr/local/pgsql/archive:

           $ pg_receivewal -h mydbserver -D /usr/local/pgsql/archive

SEE ALSO
       pg_basebackup(1)



PostgreSQL 14.23                                2026                                PG_RECEIVEWAL(1)