We are using JDK1.4.1 and connection time out is set to 30Ms and read time out to 60Ms. We are trying to connect to a IP Camera, and send a heart beat command to the camera to check for its availability every 30 Secs from the time we find it is un available. If the web server is down, we feel that HttpClient is not cleaning up failed connections properly and thats resulting in Memory Leaks at the server side.
The code we use is the standard way of using HttpClient and all the code is in a method and new HttpClient object is created for every request. Are there any ways to make sure the connections are all being purged properly? Are there any precautionary measures or flags we can set on HttpClient API when communicating with a web server (running on firm ware) with relatively less RAM and processing power (IpCamera with built in web server)?
Thanks for your time and help. Srini
Kalnichevski, Oleg wrote:
Mike and Oleg, the stack trace Srini included indicates that HttpClient is
attempting to create a new timeout thread on every connection - does this
always occur or is it just one timeout thread per httpclient instance? It
would be ideal if we could reduce this to one static thread as starting
threads is never nice for server side apps. Not sure how feasible that is
though.
Hi Srini, HttpClient uses an additional controller thread to work around the limitation of older (< 1.4) JDKs which do not provide a possibility to set connect timeout. If you do not really need to control connect timeout (for instance, when communicating with an intranet site with good availability) simply set connect timeout to. That will prevent HttpClient from spawning an additional thread per request.
Adrian, et al Another possibility to use reflection to set connect timeout using the Socket methods when running in JVM 1.4 or above
Oleg
-----Original Message----- From: Adrian Sutton [mailto:[EMAIL PROTECTED] Sent: Monday, February 02, 2004 09:03 To: Commons HttpClient Project Subject: Re: Memory Leaks when web server hangs
On 2/2/04 2:00 PM, "Srinivas Vemula" <[EMAIL PROTECTED]> wrote:
Hi All,
We are seeing thread leaks when having client open connections to a web
server that hangs. Has any one seen this happening?? How do we ensure that the
library correctly closes socket connections on failures, cleaning up system
resources, and threads actually finish in the timeout period and get freed
up. Would using MultiThreadedHttpConnectionManager
<file:///D:/silkroad/http-commons/commons-httpclient-2.0-rc3/docs/threading.ht
ml#MultiThreadedHttpConnectionManager> be of any help??
Hi Srini, If you're using the same HttpClient instance across multiple threads, you must use the MultiThreadedHttpConnectionManager or you'll run into strange problems. If you're using separate HttpClient instances, you may as well stick with the single threaded (default) connection manager.
In terms of connections hanging - you probably want to look into the setConnectionTimeout and setTimeout methods of the HttpClient class. These allow you to control how long HttpClient waits when making a connection and how long it waits for data once the connection is established. If you have set either of these to 0 (not sure what the default is, it may be platform specific) the connection will never timeout which sounds a lot like what you're seeing.
Mike and Oleg, the stack trace Srini included indicates that HttpClient is attempting to create a new timeout thread on every connection - does this always occur or is it just one timeout thread per httpclient instance? It would be ideal if we could reduce this to one static thread as starting threads is never nice for server side apps. Not sure how feasible that is though.
Srini
Regards,
Adrian Sutton.
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