Re: a problem: tomcat exits unexpectedly

[bo zhao <so...@gmail.com>]

Warnier,
    Thank you for your reply.

    AbstractScheduleTaskProcess class use the ExecutorService to create
thread and runs some custom tasks. These tasks will be done in a few
seconds. Sample code is following:

   for (final List<T> list : lists) {
            executor.submit(new Callable<Object>() {
                @Override
                public Object call() throws Exception {
                    try {
                        executeTasks(list);
                         ......

    But I don't think that this class causes the serious prolbem. the max
size of "lists" is 4 -- that is a parameter of application.

    In our server, we have 12 tomcat instances that run the different
application, but the default value of os parameter(open files and max
processes) is 1024, at first, I modified these value to 65535. but some of
these instance had still exited unexpectedly, I has found the same things
in these log:  pause, reinit, stop. So I think that the os resource limit
maybe cause all of these, especially the parameter of the "open files".

    I don't know well the tomcat, so I maybe has not found the key cause
and I expect your reply.

    Thank you very much.

On Sun, Sep 28, 2014 at 6:37 PM, André Warnier <aw...@ice-sa.com> wrote:

> bo zhao wrote:
>
>> I had modified the os ulimit parameter: open files and max processes,
>> after
>> that, Tomcat does't exit unexpectedly, and the log of Tomcat have not the
>> "... pause, ... init". It seems work normally.
>>
>> But I still don't know the reason. I want to know if the two parameter is
>> the key to solve probelm and how the two parameter of os limit cause the
>> exit of tomcat?
>>
>
> I believe that you are understanding this wrongly.  These paraneters are
> not the /cause/ of the problem, they are a /symptom/.  The default value fo
> these parameters is set so that they are ok for any normal process/system,
> and rarely need to be adjusted.
> By increasing their value, you are moving the problem further down the
> line, but are not solving the real (possible) problem.
>
> Ognjen is asking a question below. Why do you not start by answering it ?
>
>
>
>
>> On Fri, Sep 19, 2014 at 5:17 PM, Ognjen Blagojevic <
>> ognjen.d.blagojevic@gmail.com> wrote:
>>
>>  Zhao,
>>>
>>> On 19.9.2014 3:42, bo zhao wrote:
>>>
>>>  but I can't find any error message in the log? what causes the tomcat to
>>>> pause and stop?
>>>>
>>>>  One of the suspects for restarts and shutdown seems to be the class
>>> com.jd.clover.center.service.AbstractScheduleTaskProcess, as there is a
>>> log message regarding it, at the first line of each log excerpt you sent.
>>>
>>> What is AbstractScheduleTaskProcess class for?
>>>
>>> -Ognjen
>>>
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>>> For additional commands, e-mail: users-help@tomcat.apache.org
>>>
>>>
>>>
>>
>
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>

Re: a problem: tomcat exits unexpectedly

[André Warnier <aw...@ice-sa.com>]

bo zhao wrote:
> Warnier,
>     Thank you for your reply.
> 
>     AbstractScheduleTaskProcess class use the ExecutorService to create
> thread and runs some custom tasks. These tasks will be done in a few
> seconds. Sample code is following:
> 
>    for (final List<T> list : lists) {
>             executor.submit(new Callable<Object>() {
>                 @Override
>                 public Object call() throws Exception {
>                     try {
>                         executeTasks(list);
>                          ......
> 
>     But I don't think that this class causes the serious prolbem. the max
> size of "lists" is 4 -- that is a parameter of application.
> 
>     In our server, we have 12 tomcat instances that run the different
> application, but the default value of os parameter(open files and max
> processes) is 1024, at first, I modified these value to 65535. but some of
> these instance had still exited unexpectedly, I has found the same things
> in these log:  pause, reinit, stop. So I think that the os resource limit
> maybe cause all of these, especially the parameter of the "open files".
> 
>     I don't know well the tomcat, so I maybe has not found the key cause
> and I expect your reply.

In such circumstances, you can (probably) consider Tomcat as "just a process" like any 
other.  It looks like something in that process is holding on to a lot of open files/sockets.
The Linux utility "lsof" provides (among a zillion other things) a good way to list all 
the files/sockets linked to one process.
Try it for one of your Tomcat instances, and probably the names of these files/sockets 
will give you a hint.

> 
>     Thank you very much.
> 
> On Sun, Sep 28, 2014 at 6:37 PM, André Warnier <aw...@ice-sa.com> wrote:
> 
>> bo zhao wrote:
>>
>>> I had modified the os ulimit parameter: open files and max processes,
>>> after
>>> that, Tomcat does't exit unexpectedly, and the log of Tomcat have not the
>>> "... pause, ... init". It seems work normally.
>>>
>>> But I still don't know the reason. I want to know if the two parameter is
>>> the key to solve probelm and how the two parameter of os limit cause the
>>> exit of tomcat?
>>>
>> I believe that you are understanding this wrongly.  These paraneters are
>> not the /cause/ of the problem, they are a /symptom/.  The default value fo
>> these parameters is set so that they are ok for any normal process/system,
>> and rarely need to be adjusted.
>> By increasing their value, you are moving the problem further down the
>> line, but are not solving the real (possible) problem.
>>
>> Ognjen is asking a question below. Why do you not start by answering it ?
>>
>>
>>
>>
>>> On Fri, Sep 19, 2014 at 5:17 PM, Ognjen Blagojevic <
>>> ognjen.d.blagojevic@gmail.com> wrote:
>>>
>>>  Zhao,
>>>> On 19.9.2014 3:42, bo zhao wrote:
>>>>
>>>>  but I can't find any error message in the log? what causes the tomcat to
>>>>> pause and stop?
>>>>>
>>>>>  One of the suspects for restarts and shutdown seems to be the class
>>>> com.jd.clover.center.service.AbstractScheduleTaskProcess, as there is a
>>>> log message regarding it, at the first line of each log excerpt you sent.
>>>>
>>>> What is AbstractScheduleTaskProcess class for?
>>>>
>>>> -Ognjen
>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>>>> For additional commands, e-mail: users-help@tomcat.apache.org
>>>>
>>>>
>>>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>> For additional commands, e-mail: users-help@tomcat.apache.org
>>
>>
> 


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