I have a postfix system which is running fine.
However the log reports a constant pre-queue (incl message transmission)
delay (the "a" component of the log entry) of ~0.1s even for a tiny
message zero load and local 1GB connection.
This might be "normal" except that the delay reduces to ~0.01s when the
same mail is sent by a different client?!
To reduce to the simplest possible I am sending the mail like so:
echo "hello" | sendmail u...@example.org
When I do this from the machine that postfix is running on (ie using the
postfix sendmail binary replacement) or another local machine that has
the postfix binary replacement intalled, then delay is very very small
0.01s.
However...
When sending it from a machine which has Sendmail installed and I use
the sendmail "client" binary which comes with that the delay is 10x
greater ~0.1s.
I also get the larger delay when sending using a userland php library
(my actually use case).
When using my php library I was able to isolate the delay to the
END_OF_DATA command ie
<CR><LF>.<CR>LF>
Postfix's response to that command takes 0.1s if using the "Sendmail"
client or the php library. but takes only 0.01s when using the postfix
sendmail replacement library (note this is true when run from the host
that postfix server is on or a machine which is on local Gbit LAN).
Feels like some buffer is hanging waiting for more bytes and then times
out..?
I increased the verbosity of the log but could see no difference between
the use cases.
Help please!? Ideas for narrowing it down further..
Oliver
