Delay on nginx serving from backend

[cacrus]

Dear Nginx community , 

I am running nginx 1.04 , ( also tried 1.0 ) , and the backend has an
ejabber server serving http requests. 

I am experiencing delays in requests being served when i serve the
request via nginx , whereas serving the same request from the backend
works without any delay . 

On debugging , i can see that nginx received a response from backend
within milliseconds but is not serving back the user with the response .
there is a 5 second delay at this point . please find below the debug
log just before and after the delay . 

Debug Log is pasted here http://pastebin.com/S81ESzUz

Notice that there is no activity between 
06:26:33  and 06:26:38

Can anyone explain what could cause this delay .

There is no network connectivity issue between nginx and upstream , as
from the same machine when i connect directly to the backned result is
received instantly . 

I should be seeing a 400 request right away , but it takes 5-6 seconds
for the request to come .

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,203270,203270#msg-203270