.TH FLUSH 8 .ad .fi .SH NAME flush \- Postfix fast flush server .SH SYNOPSIS .na .nf \fBflush\fR [generic Postfix daemon options] .SH DESCRIPTION .ad .fi The flush server maintains a record of deferred mail by destination. This information is used to improve the performance of the SMTP \fBETRN\fR request, and of its command-line equivalent, \fBsendmail -qR\fR. This program expects to be run from the \fBmaster\fR(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 truncated when delivery is requested for the corresponding destination. A destination is the part on the right-hand side of the right-most \fB@\fR in an email address. Per-destination logfiles of deferred mail are maintained only for eligible destinations. The list of eligible destinations is specified with the \fBfast_flush_domains\fR configuration parameter, which defaults to \fB$relay_domains\fR. This server implements the following requests: .IP "\fBFLUSH_REQ_ADD\fI sitename queue_id\fR" Inform the fast flush server that the specified message is queued for \fIsitename\fR. Depending on logging policy, the fast flush server stores or ignores the information. .IP "\fBFLUSH_REQ_SEND\fI sitename\fR" Request delivery of mail that is queued for \fIsitename\fR. If the destination is eligible for a fast flush logfile, this request triggers delivery of messages listed in that destination's logfile, and the logfile is truncated to zero length; if mail is undeliverable it will be added back to the logfile. .sp If the destination is not eligible for a fast flush logfile, this request is rejected (see below for status codes). .IP \fBTRIGGER_REQ_WAKEUP\fR This wakeup request from the master is an alternative way to request \fBFLUSH_REQ_REFRESH\fR. .IP "\fBFLUSH_REQ_REFRESH\fR (completes in the background)" Refresh non-empty per-destination logfiles that were not read in \fBfast_flush_refresh_time\fR hours, by simulating send requests (see above) for the corresponding destinations. .sp Delete empty per-destination logfiles that were not updated in \fBfast_flush_purge_time\fR days. .IP "\fBFLUSH_REQ_PURGE\fR (completes in the background)" Refresh all non-empty per-destination logfiles, by simulating send requests (see above) for the corresponding destinations. This can be incredibly expensive when logging is enabled for many destinations, and is not recommended. .sp Delete empty per-destination logfiles that were not updated in \fBfast_flush_purge_time\fR days. .PP The server response is one of: .IP \fBFLUSH_STAT_OK\fR The request completed normally. .IP \fBFLUSH_STAT_BAD\fR The flush server rejected the request (bad request name, bad request parameter value). .IP \fBFLUSH_STAT_FAIL\fR The request failed. .IP \fBFLUSH_STAT_DENY\fR The request was denied because the destination domain is not eligible for fast flush service, or because the fast flush service is disabled. .SH SECURITY .na .nf .ad .fi 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. .SH DIAGNOSTICS .ad .fi Problems and transactions are logged to \fBsyslogd\fR(8). .SH BUGS .ad .fi Fast flush logfiles are truncated only after a \fBFLUSH_REQ_SEND\fR request, not when mail is actually delivered, and therefore can accumulate outdated or redundant data. In order to maintain sanity, \fBFLUSH_REQ_REFRESH\fR must be executed periodically. This can be automated with a suitable wakeup timer setting in the \fBmaster.cf\fR configuration file. Upon receipt of a request to deliver all mail for an eligible destination, the \fBflush\fR 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 \fBrelay_domains\fR destination because such mail typically only has recipients in one domain. .SH FILES .na .nf /var/spool/postfix/flush, location of "fast flush" logfiles. .SH CONFIGURATION PARAMETERS .na .nf .ad .fi See the Postfix \fBmain.cf\fR file for syntax details and for default values. Use the \fBpostfix reload\fR command after a configuration change. .IP \fBfast_flush_domains\fR What destinations can have a "fast flush" logfile. By default, this is set to \fB$relay_domains\fR. .IP \fBfast_flush_refresh_time\fR Refresh a non-empty "fast flush" logfile that was not read in this amount of time (default time unit: hours), by simulating a send request for the corresponding destination. .IP \fBfast_flush_purge_time\fR Remove an empty "fast flush" logfile that was not updated in this amount of time (default time unit: days). .IP \fBparent_domain_matches_subdomains\fR List of Postfix features that use \fIdomain.tld\fR patterns to match \fIsub.domain.tld\fR (as opposed to requiring \fI.domain.tld\fR patterns). .SH SEE ALSO .na .nf smtpd(8) Postfix SMTP server qmgr(8) Postfix queue manager syslogd(8) system logging .SH LICENSE .na .nf .ad .fi The Secure Mailer license must be distributed with this software. .SH AUTHOR(S) .na .nf Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA