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FLUSH(8) FLUSH(8)
<b>NAME</b>
flush - Postfix fast flush server
<b>SYNOPSIS</b>
<b>flush</b> [generic Postfix daemon options]
<b>DESCRIPTION</b>
The <a href="flush.8.html"><b>flush</b>(8)</a> server maintains a record of deferred mail by destination.
This information is used to improve the performance of the SMTP <b>ETRN</b>
request, and of its command-line equivalent, "<b>sendmail -qR</b>" or
"<b>postqueue -f</b>". This program expects to be run from the <a href="master.8.html"><b>master</b>(8)</a>
process manager.
The record is implemented as a per-destination logfile with as contents
the queue IDs of deferred mail. A logfile is append-only, and is trun-
cated when delivery is requested for the corresponding destination. A
destination is the part on the right-hand side of the right-most <b>@</b> in
an email address.
Per-destination logfiles of deferred mail are maintained only for eli-
gible destinations. The list of eligible destinations is specified with
the <b><a href="postconf.5.html#fast_flush_domains">fast_flush_domains</a></b> configuration parameter, which defaults to
<b>$<a href="postconf.5.html#relay_domains">relay_domains</a></b>.
This server implements the following requests:
<b>add</b> <i>sitename queueid</i>
Inform the <a href="flush.8.html"><b>flush</b>(8)</a> server that the message with the specified
queue ID is queued for the specified destination.
<b>send_site</b> <i>sitename</i>
Request delivery of mail that is queued for the specified desti-
nation.
<b>send_file</b> <i>queueid</i>
Request delivery of the specified deferred message.
<b>refresh</b>
Refresh non-empty per-destination logfiles that were not read in
<b>$<a href="postconf.5.html#fast_flush_refresh_time">fast_flush_refresh_time</a></b> hours, by simulating send requests (see
above) for the corresponding destinations.
Delete empty per-destination logfiles that were not updated in
<b>$<a href="postconf.5.html#fast_flush_purge_time">fast_flush_purge_time</a></b> days.
This request completes in the background.
<b>purge</b> Do a <b>refresh</b> for all per-destination logfiles.
<b>SECURITY</b>
The <a href="flush.8.html"><b>flush</b>(8)</a> server is not security-sensitive. It does not talk to the
network, and it does not talk to local users. The fast flush server
can run chrooted at fixed low privilege.
<b>DIAGNOSTICS</b>
Problems and transactions are logged to <b>syslogd</b>(8) or <a href="postlogd.8.html"><b>postlogd</b>(8)</a>.
<b>BUGS</b>
Fast flush logfiles are truncated only after a "send" request, not when
mail is actually delivered, and therefore can accumulate outdated or
redundant data. In order to maintain sanity, "refresh" must be executed
periodically. This can be automated with a suitable wakeup timer set-
ting in the <a href="master.5.html"><b>master.cf</b></a> configuration file.
Upon receipt of a request to deliver mail for an eligible destination,
the <a href="flush.8.html"><b>flush</b>(8)</a> server requests delivery of all messages that are listed
in that destination's logfile, regardless of the recipients of those
messages. This is not an issue for mail that is sent to a <b><a href="postconf.5.html#relay_domains">relay_domains</a></b>
destination because such mail typically only has recipients in one
domain.
<b>CONFIGURATION PARAMETERS</b>
Changes to <a href="postconf.5.html"><b>main.cf</b></a> are picked up automatically as <a href="flush.8.html"><b>flush</b>(8)</a> processes
run for only a limited amount of time. Use the command "<b>postfix reload</b>"
to speed up a change.
The text below provides only a parameter summary. See <a href="postconf.5.html"><b>postconf</b>(5)</a> for
more details including examples.
<b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
The default location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
figuration files.
<b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
How much time a Postfix daemon process may take to handle a
request before it is terminated by a built-in watchdog timer.
<b><a href="postconf.5.html#fast_flush_domains">fast_flush_domains</a> ($<a href="postconf.5.html#relay_domains">relay_domains</a>)</b>
Optional list of destinations that are eligible for per-destina-
tion logfiles with mail that is queued to those destinations.
<b><a href="postconf.5.html#fast_flush_refresh_time">fast_flush_refresh_time</a> (12h)</b>
The time after which a non-empty but unread per-destination
"fast flush" logfile needs to be refreshed.
<b><a href="postconf.5.html#fast_flush_purge_time">fast_flush_purge_time</a> (7d)</b>
The time after which an empty per-destination "fast flush" log-
file is deleted.
<b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
The time limit for sending or receiving information over an
internal communication channel.
<b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
The maximum amount of time that an idle Postfix daemon process
waits for an incoming connection before terminating voluntarily.
<b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
The maximal number of incoming connections that a Postfix daemon
process will service before terminating voluntarily.
<b><a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a> (see 'postconf -d' output)</b>
A list of Postfix features where the pattern "example.com" also
matches subdomains of example.com, instead of requiring an
explicit ".example.com" pattern.
<b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
The process ID of a Postfix command or daemon process.
<b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b>
The process name of a Postfix command or daemon process.
<b><a href="postconf.5.html#queue_directory">queue_directory</a> (see 'postconf -d' output)</b>
The location of the Postfix top-level queue directory.
<b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
The syslog facility of Postfix logging.
<b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
A prefix that is prepended to the process name in syslog
records, so that, for example, "smtpd" becomes "prefix/smtpd".
Available in Postfix 3.3 and later:
<b><a href="postconf.5.html#service_name">service_name</a> (read-only)</b>
The <a href="master.5.html">master.cf</a> service name of a Postfix daemon process.
<b>FILES</b>
/var/spool/postfix/flush, "fast flush" logfiles.
<b>SEE ALSO</b>
<a href="smtpd.8.html">smtpd(8)</a>, SMTP server
<a href="qmgr.8.html">qmgr(8)</a>, queue manager
<a href="postconf.5.html">postconf(5)</a>, configuration parameters
<a href="master.5.html">master(5)</a>, generic daemon options
<a href="master.8.html">master(8)</a>, process manager
<a href="postlogd.8.html">postlogd(8)</a>, Postfix logging
syslogd(8), system logging
<b>README FILES</b>
<a href="ETRN_README.html">ETRN_README</a>, Postfix ETRN howto
<b>LICENSE</b>
The Secure Mailer license must be distributed with this software.
<b>HISTORY</b>
This service was introduced with Postfix version 1.0.
<b>AUTHOR(S)</b>
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
Wietse Venema
Google, Inc.
111 8th Avenue
New York, NY 10011, USA
FLUSH(8)
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