Hello Srini,
you should *not* create a new HTTP Client for each request!
This will also create a new connection manager, and a new
cleanup thread. It beats the whole purpose of connection
management.
You should create *one* HTTP Client object for the lifetime
of your application. Then, the connection manager of that
client will reuse and free connections as appropriate.
best regards,
Roland
Srinivas Vemula <[EMAIL PROTECTED]>
02.02.2004 11:56
Please respond to "Commons HttpClient Project"
To: Commons HttpClient Project
<[EMAIL PROTECTED]>
cc:
Subject: Re: Memory Leaks when web server hangs
Oleg,
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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