The xdelay=
syslog equate shows the amount of time the
current total transaction took. This could be the amount of time the
message took to be transmitted during its successful, final delivery,
or the amount of time the message took to be deferred because of a
transient error. This differs from delay= in that
delay= shows the total amount of time the message
took, computed from when the message was originally received or
queued (this could be days ago), until it was eventually delivered.
In the case of SMTP mail, the xdelay= computation
starts when sendmail starts trying to connect to
the remote host. In the case of locally delivered mail, the
computation starts when sendmail executes the
delivery agent. The computation ends when the dot is accepted at the
close of the DATA SMTP phase or when the local delivery agent exits,
and is typically a few seconds.
The form of the xdelay= looks like this:
xdelay=HH:MM:SS
The time expression shows the hours (HH), minutes
(MM), and seconds (SS) it took
to perform delivery via the final delivery agent. In the case of
networked mail, that interval can be long but usually
isn't:
xdelay=00:41:05 sometimes a bit long
xdelay=00:00:02 usually swift
But in the case of locally delivered mail, this interval can seem
instantaneous:
xdelay=00:00:00
Note that the xdelay= syslog
equate is shown only for recipient records.