On Thu, 2015-06-04 at 15:32 -0700, Check Peck wrote:
@Michael: Thanks for your suggestion. Can you explain me why do you think,
it's a TCP issue? I was assuming may be the way I am using RestTemplate in
my code might not be right and that's why it might be resulting in
TIME_WAIT connections a lot on the machine where I have my code deployed
which makes Http Call to my RestService? In the company I am working here,
they have their own Parent POM in which they have spring dependency, the
latest I can get for Spring is 3.2.8: I am not sure whether Spring 3.2.8
uses new version of HttpClient or not. I did check the first github link
you provided but I was not able to find ivy.xml file in 3.2.x branch so
cannot confirm that. May be you know some other way to confirm that. I can
use Spring 3.2.8 version max here. And also, do you see any issues with the
way I am using RestTemplate here, I am just using default way of making
HttpClient calls, may be I need to have some sort of extra parameter to
resolve this issue? Are there anything I need to set while making
RestTemplate calls like Connection: close or keep-alive anything like
this? And also do you think the way I am using RestTemplate will reuse/pool
my client connections or not?
@Stefan: I am using RestTemplate in default way as shown in my above code.
I am assuming, it will be reusing/pooling my connections right? I did
google the issue and I found out lot of things, like lowering down the
tcp_fin_timeout value from 60 to 30 and some other stuff as mentioned
here in this article:
http://www.fromdual.com/huge-amount-of-time-wait-connections
But I was trying to confirm whether it might be related to how I am using
RestTemplate or it is a OS issue? If I can confirm it's an OS issue, then I
will look into that and if let's say the way I am using RestTemplate is not
right, then I might try improving my code to see whether the problem goes
away or not. I am thinking may be the way I am using RestTemplate is not
right? May be I need to have keep-alive options on?
Connections in TIME_WAIT are perfectly normal depending on your OS
systems and do not represent an issue with HttpClient resource
management.
For details see
http://wiki.apache.org/HttpComponents/FrequentlyAskedConnectionManagementQuestions
Oleg
On Thu, Jun 4, 2015 at 12:52 PM, Stefan Magnus Landrø
stefan.lan...@gmail.com wrote:
I presume you are reusing/pooling your client connections, right?
Also - you could tune your OS to shutdown connections faster. You can
easily google you issue.
Stefan
2015-06-04 17:51 GMT+02:00 Check Peck comptechge...@gmail.com:
I am using Spring RestTemplate to make a HTTP Calls to my RestService. I
am
using spring framework 3.1.1 version of RestTemplate. I cannot upgrade
this
since that's what we are using in our company.
Now machine which is running my code (which uses RestTemplate) to make
call
to my RestService, I see lot of TIME_WAIT connections opened on that
particular machine?
- Is there any reason why it happens with RestTemplate or the way I am
using it?
- Also, what is the connection between TIME_WAIT and HTTP Client calls to
my RestService? I am not able to understand this as well. Does HTTP Calls
has any significance on TIME_WAIT? There might be some theoretical
explanation for this I guess.
Below is how I am using RestTemplate in my code base:
public class DataClient implements Client {
private final RestTemplate restTemplate = new RestTemplate();
private ExecutorService executor =
Executors.newFixedThreadPool(10);
// for synchronous call
@Override
public String getSyncData(DataKey key) {
String response = null;
FutureString handler = null;
try {
handler = getAsyncData(key);
response = handler.get(key.getTimeout(),
TimeUnit.MILLISECONDS);
} catch (TimeoutException ex) {
// log an exception
handler.cancel(true);
} catch (Exception ex) {
// log an exception
}
return response;
}
// for asynchronous call
@Override
public FutureString getAsyncData(DataKey key) {
FutureString future = null;
try {
Task task = new Task(key, restTemplate);
future = executor.submit(task);
} catch (Exception ex) {
// log an exception
}
return future;
}
}
And below is my simple Task class
class Task implements CallableString {
private final RestTemplate restTemplate;
private final DataKey key;
public Task(DataKey key, RestTemplate restTemplate) {
