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Posted to dev@cocoon.apache.org by Stuart Roebuck <st...@adolos.co.uk> on 2001/04/05 20:22:44 UTC
[C2] Problems with more than 10 simultaneous image requests
I'm coming across a problem when the current CVS of C2 is put under heavy
load. I wonder whether it could be something to do with the component
pooling. It appears as thought there may be a problem when more than
about 10 images are requested simultaneously.
Any thoughts?
The net result is that pages loaded during the heavy load period exhibit
missing images, as if the requests have been refused rather than delayed.
Reaccessing the page brings the images back no problem.
I'm sorry that I'm just generating bug reports at the moment and not doing
much to follow them through. Hopefully I'll have a bit more time sometime
soon!
Stuart.
-------------------------------------------------------------------------
Stuart Roebuck stuart.roebuck@adolos.com
Lead Developer Java, XML, MacOS X, XP, etc.
ADOLOS http://www.adolos.com/
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Re: [C2] Problems with more than 10 simultaneous image requests
Posted by Berin Loritsch <bl...@apache.org>.
Stuart Roebuck wrote:
>
> This is just a single client calling up the images of a single page. I've
> just spent a bit of time looking for an exception and had problems
> reproducing the fault for a while, but I think this is it:
I narrowed down the problem. It had to do with the Lock class not doing what
it was designed to do. I completely reimplemented it (it blocks until
it is unlocked), and slammed my personal server with JMeter. I was quite
pleased to see that performance almost doubled due to the inneficiency of
storing locks in a Hashtable.
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Re: [C2] Problems with more than 10 simultaneous image requests
Posted by Stuart Roebuck <st...@adolos.co.uk>.
On Friday, April 6, 2001, at 01:36 pm, Berin Loritsch wrote:
> Stuart Roebuck wrote:
>>
>> On Thursday, April 5, 2001, at 07:34 pm, Berin Loritsch wrote:
>>
>>> Stuart Roebuck wrote:
>>>>
>>>> I'm coming across a problem when the current CVS of C2 is put under
>>>> heavy
>>>> load. I wonder whether it could be something to do with the component
>>>> pooling. It appears as thought there may be a problem when more than
>>>> about 10 images are requested simultaneously.
>>>>
>>>> Any thoughts?
>>>>
>>>> The net result is that pages loaded during the heavy load period
>>>> exhibit
>>>> missing images, as if the requests have been refused rather than
>>>> delayed.
>>>> Reaccessing the page brings the images back no problem.
>>>>
>>>> I'm sorry that I'm just generating bug reports at the moment and not
>>>> doing
>>>> much to follow them through. Hopefully I'll have a bit more time
>>>> sometime
>>>> soon!
>>>
>>> Are you using the DatabaseReader or the ResourceReader?
>>
>> ResourceReader.
>
> What is the load that exibited this behavior? How many requests/second,
> simultaneous clients, etc.? I have a feeling that this may be tied to
> the Pool throwing an exception when too many demands are placed on it,
> which means that I need to slam that thing to reproduce the error (and
> lower the number of cached instances).
This is just a single client calling up the images of a single page. I've
just spent a bit of time looking for an exception and had problems
reproducing the fault for a while, but I think this is it:
ERROR 24369 [cocoon ] (HttpProcessor[8080][1]): Problem with servlet
java.lang.IndexOutOfBoundsException: Index: 4, Size: 4
at java.util.ArrayList.RangeCheck(ArrayList.java:491)
at java.util.ArrayList.remove(ArrayList.java:375)
at
org.apache.cocoon.components.ComponentPool.put(ComponentPool.java:192)
at
org.apache.cocoon.components.CocoonComponentHandler.put
(CocoonComponentHandler.java:174)
at
org.apache.cocoon.components.CocoonComponentManager.release
(CocoonComponentManager.java:218)
at
org.apache.cocoon.www.sitemap_xmap.process(sitemap_xmap.java:952)
at org.apache.cocoon.sitemap.Handler.process(Handler.java:153)
at org.apache.cocoon.sitemap.Manager.invoke(Manager.java:107)
at org.apache.cocoon.Cocoon.process(Cocoon.java:218)
at
org.apache.cocoon.servlet.CocoonServlet.service(CocoonServlet.java:425)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter
(ApplicationFilterChain.java:246)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter
(ApplicationFilterChain.java:191)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.
java:255)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:
566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:879)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.
java:225)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:
566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:879)
at org.apache.catalina.core.StandardContext.invoke(StandardContext.
java:2175)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:
566)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.
java:446)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:
564)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:879)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:
162)
at
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:
566)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:472)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:879)
at
org.apache.catalina.connector.http.HttpProcessor.process(HttpProcessor.java:
827)
at
org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.java:904)
at java.lang.Thread.run(Thread.java:496)
Stuart.
-------------------------------------------------------------------------
Stuart Roebuck, BSc, MBA Tel.: 0131 228 4853 / Fax.: 0870 054 8322
Managing Director Alpha Numeric Pager: 07654 588898
ADOLOS http://www.adolos.com/
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Re: [C2] Problems with more than 10 simultaneous image requests
Posted by Berin Loritsch <bl...@apache.org>.
Stuart Roebuck wrote:
>
> On Thursday, April 5, 2001, at 07:34 pm, Berin Loritsch wrote:
>
> > Stuart Roebuck wrote:
> >>
> >> I'm coming across a problem when the current CVS of C2 is put under heavy
> >> load. I wonder whether it could be something to do with the component
> >> pooling. It appears as thought there may be a problem when more than
> >> about 10 images are requested simultaneously.
> >>
> >> Any thoughts?
> >>
> >> The net result is that pages loaded during the heavy load period exhibit
> >> missing images, as if the requests have been refused rather than delayed.
> >> Reaccessing the page brings the images back no problem.
> >>
> >> I'm sorry that I'm just generating bug reports at the moment and not
> >> doing
> >> much to follow them through. Hopefully I'll have a bit more time
> >> sometime
> >> soon!
> >
> > Are you using the DatabaseReader or the ResourceReader?
>
> ResourceReader.
What is the load that exibited this behavior? How many requests/second,
simultaneous clients, etc.? I have a feeling that this may be tied to
the Pool throwing an exception when too many demands are placed on it,
which means that I need to slam that thing to reproduce the error (and
lower the number of cached instances).
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Re: [C2] Problems with more than 10 simultaneous image requests
Posted by Stuart Roebuck <st...@adolos.co.uk>.
On Thursday, April 5, 2001, at 07:34 pm, Berin Loritsch wrote:
> Stuart Roebuck wrote:
>>
>> I'm coming across a problem when the current CVS of C2 is put under heavy
>> load. I wonder whether it could be something to do with the component
>> pooling. It appears as thought there may be a problem when more than
>> about 10 images are requested simultaneously.
>>
>> Any thoughts?
>>
>> The net result is that pages loaded during the heavy load period exhibit
>> missing images, as if the requests have been refused rather than delayed.
>> Reaccessing the page brings the images back no problem.
>>
>> I'm sorry that I'm just generating bug reports at the moment and not
>> doing
>> much to follow them through. Hopefully I'll have a bit more time
>> sometime
>> soon!
>
> Are you using the DatabaseReader or the ResourceReader?
ResourceReader.
-------------------------------------------------------------------------
Stuart Roebuck stuart.roebuck@adolos.com
Lead Developer Java, XML, MacOS X, XP, etc.
ADOLOS http://www.adolos.com/
---------------------------------------------------------------------
To unsubscribe, e-mail: cocoon-dev-unsubscribe@xml.apache.org
For additional commands, email: cocoon-dev-help@xml.apache.org
Re: [C2] Problems with more than 10 simultaneous image requests
Posted by Berin Loritsch <bl...@apache.org>.
Stuart Roebuck wrote:
>
> I'm coming across a problem when the current CVS of C2 is put under heavy
> load. I wonder whether it could be something to do with the component
> pooling. It appears as thought there may be a problem when more than
> about 10 images are requested simultaneously.
>
> Any thoughts?
>
> The net result is that pages loaded during the heavy load period exhibit
> missing images, as if the requests have been refused rather than delayed.
> Reaccessing the page brings the images back no problem.
>
> I'm sorry that I'm just generating bug reports at the moment and not doing
> much to follow them through. Hopefully I'll have a bit more time sometime
> soon!
Are you using the DatabaseReader or the ResourceReader?
>
> Stuart.
>
> -------------------------------------------------------------------------
> Stuart Roebuck stuart.roebuck@adolos.com
> Lead Developer Java, XML, MacOS X, XP, etc.
> ADOLOS http://www.adolos.com/
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: cocoon-dev-unsubscribe@xml.apache.org
> For additional commands, email: cocoon-dev-help@xml.apache.org
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