hello everyone,

sorry for the long post, but i am stumped and i want to be as precise as 

this is my setup:
php 4.2.0 with the socket extension, as a dynamically loaded module in 
apache 1.3.23. it is running on is a red hat 7.0 box with kernel 2.2.19.

this is was i am trying to do:
i am using the socket functions to connect to a server which is running a 
ticketing software using a specifically designed protocol; the details do 
not matter here. i'll call my webserver "webserv.com", the client calling 
the script "client.com" and the ticketsystem "tixserv.com".

i think i am doing everything by the book - just a simple one-shot 
tcp-client; writing some request to tixserv.com, reading the response and 
closing the connection. i am using socket_create(), socket_connect(), 
socket_write(), socket_read(), and finally socket_close(), pretty much the 
same way as the example 2 ("Simple TCP/IP client") in the php manual. this 
seems to work well (no errors or warnings).

this is my problem:
if i monitor the connection attempts with netstat, i am seeing the 
following behaviour:

firstly, connections are established: from webserv.com to client.com and 
from webserv.com to tixserv.com:

tcp    webserv.com:1558     tixserv.com:45007    SYN_SENT    1126/httpd 

tcp    webserv.com:www      client.com:1894      ESTABLISHED 

then, the connection from webserv.com to tixserv.com is closed (using 
socket_close() in the script), so the connection status goes to TIME_WAIT:

tcp    webserv.com:1558     tixserv.com:45007    TIME_WAIT   - 

tcp    webserv.com:www      client.com:1894      ESTABLISHED 

i see that to go to TIME_WAIT status is the correct way to behave for a 
socket. but the problem is that httpd somehow seems to wait for the 
TIME_WAIT status to go away and keeps the connection open during this time 
(ESTABLISHED). this takes a really long time (at least 30 seconds or more). 
at some time, the TIME_WAIT of the connection to tixserv.com finally goes 
away, and the connection to the client falls into that state:

tcp    webserv.com:www      client.com:1894      TIME_WAIT   - 

strange - my browser and php seem to ignore this: the script execution, 
measured with microtime(), is around 800 miliseconds, of which at least 90% 
is response time by tixserv.com which is fine. also, my browser does not 
need more than a second to display the script results. nonetheless, the 
httpd connection on the server stays ESTABLISHED for at least 30 seconds.

the scary thing about this is that it gets worse if i start to stress the 
server. i used jakarta-jmeter to simulate simultaneous requests. jmeter did 
not behave the same as my browser: it actually waited until the httpd 
connection status was really closed. this totally stressed webserv.com: i 
had response times around 600 seconds and more, with only 5 threads doing 2 
requests for the script. the load on webserv.com was huge during that time, 
sometimes i even had to stop apache to end the test.

i am not sure if this is a bug or a problem of my code/concept. ideas, anyone?

regards, guido 

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