Hi,

My configuration is: Mac OS X Server 10.3.9 with WebObjects Deployment 5.2.3
and Apache 1.3.33

>From time to time this system runs to a problem with growing number of httpd
processes being in CLOSE_WAIT state which eventually leads to denial of http
service due to the limit of maximum simultaneous connections of web service.

The output of netstat command in such situations looks like this:
tcp4       0      0  server.80        remote_client1.high_port    CLOSE_WAIT
tcp4       0      0  server.80        remote_client2.high_port    CLOSE_WAIT
...

I've tried to track down the requests of one of the remote clients by
looking at the logs by it's ip and found out that this request was made 15
hours before the problem. This request was made during high-load on server
(backup which involved copying of large files) and it took about 3 minutes
for WO application instance to process this request. The processing was
followed by "Broken pipe" exception as expected:

2006-02-12 10:13:02,001 WARN  AppName[29116:2010 47] [WorkerThread79]
(ERXNSLogLog4jBridge.java:41)  - <WOWorkerThread id=79
socket=Socket[addr=/127.0.0.1,port=57708,localport=2010]> Exception while
sending response: java.net.SocketException: Broken pipe

Naturally, this time was greater than the timeout defined in "HTTP Adaptor
Settings" in Monitor, so remote client got a redirect to "Redirection URL"
defined in Monitor:

server_name server_ip - - [12/Feb/2006:10:03:31 +0300] "GET /requestUrl
HTTP/1.0" 302 0 "-" "Mozilla/5.0 (compatible; Yahoo! Slurp;
http://help.yahoo.com/help/us/ysearch/slurp)" -

The steps outlined above presumably lead to http process getting stuck in
CLOSE_WAIT state for 15 hours. Later when httpd service became unavailble it
was manually killed along with others by apachectl restart.

Right now I suspect that other requests from ip addresses in netstat output
have similar history which means that long responses of application during
high load lead to rapid growth of the number of httpd processes and denial
of service.

Can this be a problem of WebObjects Adaptor? What are the possible
solutions?

---
Denis Frolov
Media Agency Design Maximum

Tel: +7 863 2648211
Fax: +7 863 2645229
Web: http://www.designmaximum.com



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