SYNOPSIS

       flush [generic Postfix daemon options]

DESCRIPTION

       The  flush  server  maintains a record of deferred mail by destination.
       This information is used to improve the performance of  the  SMTP  ETRN
       request,   and  of  its  command-line  equivalent,  "sendmail  -qR"  or
       "postqueue -f".  This program expects to  be  run  from  the  master(8)
       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  @  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  fast_flush_domains  configuration  parameter,  which  defaults  to
       $relay_domains.

       This server implements the following requests:

       add sitename queueid
              Inform the fast flush server that the message with the specified
              queue ID is queued for the specified destination.

       send sitename
              Request delivery of mail that is queued for the specified desti-
              nation.

       refresh
              Refresh non-empty per-destination logfiles that were not read in
              $fast_flush_refresh_time hours, by simulating send requests (see
              above) for the corresponding destinations.

              Delete empty per-destination logfiles that were not  updated  in
              $fast_flush_purge_time days.

              This request completes in the background.

       purge  Do a refresh for all per-destination logfiles.

SECURITY

       The  fast  flush  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.

DIAGNOSTICS

       Problems and transactions are logged to syslogd(8).

BUGS

       Changes to main.cf are picked up automatically  as  flush(8)  processes
       run for only a limited amount of time. Use the command "postfix reload"
       to speed up a change.

       The text below provides only a parameter summary. See  postconf(5)  for
       more details including examples.

       config_directory (see 'postconf -d' output)
              The  default  location of the Postfix main.cf and master.cf con-
              figuration files.

       daemon_timeout (18000s)
              How much time a Postfix daemon process  may  take  to  handle  a
              request before it is terminated by a built-in watchdog timer.

       fast_flush_domains ($relay_domains)
              Optional list of destinations that are eligible for per-destina-
              tion logfiles with mail that is queued to those destinations.

       fast_flush_refresh_time (12h)
              The time after which  a  non-empty  but  unread  per-destination
              "fast flush" logfile needs to be refreshed.

       fast_flush_purge_time (7d)
              The  time after which an empty per-destination "fast flush" log-
              file is deleted.

       ipc_timeout (3600s)
              The time limit for sending  or  receiving  information  over  an
              internal communication channel.

       max_idle (100s)
              The  maximum  amount of time that an idle Postfix daemon process
              waits for the next service request before exiting.

       max_use (100)
              The maximal number of connection requests before a Postfix  dae-
              mon process terminates.

       parent_domain_matches_subdomains (see 'postconf -d' output)
              What Postfix features match subdomains of "domain.tld" automati-
              cally, instead of requiring an explicit ".domain.tld" pattern.

       process_id (read-only)
              The process ID of a Postfix command or daemon process.

       process_name (read-only)
              The process name of a Postfix command or daemon process.

       queue_directory (see 'postconf -d' output)
              The location of the Postfix top-level queue directory.

       postconf(5), configuration parameters
       master(8), process manager
       syslogd(8), system logging

README FILES

       Use "postconf readme_directory" or "postconf html_directory" to  locate
       this information.
       ETRN_README, Postfix ETRN howto

LICENSE

       The Secure Mailer license must be distributed with this software.

HISTORY

       This service was introduced with Postfix version 1.0.

AUTHOR(S)

       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA



                                                                      FLUSH(8)