NAME

       pg_receivexlog - streams transaction logs from a PostgreSQL cluster

SYNOPSIS

       pg_receivexlog [option...]

DESCRIPTION

       pg_receivexlog is used to stream transaction log from a running PostgreSQL cluster. The
       transaction 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 24.3, “Continuous Archiving and Point-
       in-Time Recovery (PITR)”, in the documentation).

       pg_receivexlog streams the transaction 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_receivexlog.

       The transaction log is streamed over a regular PostgreSQL connection, and uses the
       replication protocol. The connection must be made with a superuser or a user having
       REPLICATION permissions (see Section 20.2, “Role Attributes”, in the documentation), and
       pg_hba.conf must explicitly 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.

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

OPTIONS

       The following command-line options control the location and format of the output.

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

           This parameter is required.

       The following command-line options control the running of the program.

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

       -v, --verbose
           Enables verbose mode.

       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. See
           Section 31.1.1, “Connection Strings”, in the documentation for more information.

           The option is called --dbname for consistency with other client applications, but
           because pg_receivexlog 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.

       -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.

       -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_receivexlog to prompt for a password before connecting to a database.

           This option is never essential, since pg_receivexlog will automatically prompt for a
           password if the server demands password authentication. However, pg_receivexlog 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.

       Other options are also available:

       -V, --version
           Print the pg_receivexlog version and exit.

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

ENVIRONMENT

       This utility, like most other PostgreSQL utilities, uses the environment variables
       supported by libpq (see Section 31.14, “Environment Variables”, in the documentation).

NOTES

       When using pg_receivexlog instead of archive_command, the server will continue to recycle
       transaction log files even if the backups are not properly archived, since there is no
       command that fails. This can be worked around by having an archive_command that fails when
       the file has not been properly archived yet, for example:

           archive_command = 'sleep 5 && test -f /mnt/server/archivedir/%f'

       The initial timeout is necessary because pg_receivexlog works using asynchronous
       replication and can therefore be slightly behind the master.

EXAMPLES

       To stream the transaction log from the server at mydbserver and store it in the local
       directory /usr/local/pgsql/archive:

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

SEE ALSO

       pg_basebackup(1)