Releasing connections

[Joan Balaguero <jo...@grupoventus.com>]

Hello,

 

I’ve implemented the following code to send a request, read the response and
returns back the connection to the pool:

 

(…)

Try

{

 (…)

 entity  = this.objHttp.execute(objPost));

  

 if (entity != null)

 {

  bis                   = new BufferedInputStream(entity.getContent());

  ByteArrayOutputStream buffer = new
ByteArrayOutputStream(httpOutBufferSize);

  byte[] tmp            = new byte[httpOutBufferSize];

  int numBytesRead      = 0;

 

  while ((numBytesRead = bis.read(tmp)) >= 0) buffer.write(tmp, 0,
numBytesRead);

  bis.close();

  bis = null;

 }

}

Catch (Exception e) {  throw new ProxyServletException(); }

Finally

{

 If (bis != null)

 {

  Try { bis.close(); bis = null; } catch (Exception e1) {}

 }

 

 If (entity != null)

 {

  Try { entity.consumeContent(); } catch (Exception e1) {}

 }

}

 

With this code:

 

1.       The connection is returned back to the pool correctly (the pool
never becomes exhausted).

2.       But I have more and more instances of java.net.* classes in my heap
histogram:

 

For example:

SockSocketImpl (number of instances)

12:30     19.517

13:30     70.731

14:00   107.061

 

SocketInputStream

12:30           907

13:30     68.650

14:00   103.568

 

 

It seems that the connection is returned back to the pool but the resources
associated with the http response are not freed up. At 12:20 I started
Tomcat, and the load from 12:20 since now is similar.

 

Is there any error in my code that I’m not able to see?

 

Thanks in advance,

 

Joan.

 

Re: Releasing connections

[Oleg Kalnichevski <ol...@apache.org>]

Joan Balaguero wrote:
> Hello,
> 
>  
> 
> I’ve implemented the following code to send a request, read the response and
> returns back the connection to the pool:
> 
>  
> 
> (…)
> 
> Try
> 
> {
> 
>  (…)
> 
>  entity  = this.objHttp.execute(objPost));
> 
>   
> 
>  if (entity != null)
> 
>  {
> 
>   bis                   = new BufferedInputStream(entity.getContent());
> 
>   ByteArrayOutputStream buffer = new
> ByteArrayOutputStream(httpOutBufferSize);
> 
>   byte[] tmp            = new byte[httpOutBufferSize];
> 
>   int numBytesRead      = 0;
> 
>  
> 
>   while ((numBytesRead = bis.read(tmp)) >= 0) buffer.write(tmp, 0,
> numBytesRead);
> 
>   bis.close();
> 
>   bis = null;
> 
>  }
> 
> }
> 
> Catch (Exception e) {  throw new ProxyServletException(); }
> 
> Finally
> 
> {
> 
>  If (bis != null)
> 
>  {
> 
>   Try { bis.close(); bis = null; } catch (Exception e1) {}
> 
>  }
> 
>  
> 
>  If (entity != null)
> 
>  {
> 
>   Try { entity.consumeContent(); } catch (Exception e1) {}
> 
>  }
> 
> }
> 
>  
> 
> With this code:
> 
>  
> 
> 1.       The connection is returned back to the pool correctly (the pool
> never becomes exhausted).
> 
> 2.       But I have more and more instances of java.net.* classes in my heap
> histogram:
> 
>  

Joan

There is no need for so much code. Reliable connection release can be 
implemented much simpler:

http://svn.apache.org/repos/asf/httpcomponents/httpclient/tags/4.0.1/httpclient/src/examples/org/apache/http/examples/client/ClientConnectionRelease.java



> 
> For example:
> 
> SockSocketImpl (number of instances)
> 
> 12:30     19.517
> 
> 13:30     70.731
> 
> 14:00   107.061
> 
>  
> 
> SocketInputStream
> 
> 12:30           907
> 
> 13:30     68.650
> 
> 14:00   103.568
> 
>  
> 
>  
> 
> It seems that the connection is returned back to the pool but the resources
> associated with the http response are not freed up. At 12:20 I started
> Tomcat, and the load from 12:20 since now is similar.
> 
>  
> 
> Is there any error in my code that I’m not able to see?
> 
>  

HttpClient is not known to leak SockSocketImpl instances. In any way, 
please upgrade to the latest SVN snapshot of HttpCore and re-test your 
application.

http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/

If the problem persists please try to gather more information about the 
problem by turning on context logging for connection management / 
request execution as described here:

http://hc.apache.org/httpcomponents-client-4.0.1/logging.html

Oleg

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