For what it is worth I saw a file being created in the URLResourceStream constructor at line 88 but it doesn't look like this is the source of any problems, its just a way to figure out how to check the lastModified time later on.
While I can't claim any kind of expertise on the inner workings of Wicket it seems that this problem would be solved if it wasn't required to check the last modification time on those resources which are embedded in the Wicket jar. Of course I have no idea what else this would affect so it may not be so simple. It may also be possible to just cache the stream or the actual .js string for use by later requests so that it is not necessary to try and reload files like this from the jar every time they are requested. For our use what we are likely going to do is pull the .js files out and place them where httpd can serve them and then use some url rewriting magic to prevent Wicket from serving them. Adam igor.vaynberg wrote: > > i just dont see what we can do about this... we are calling > connection.getLastModified(), we are not creating a file, etc... > > -igor > > On Wed, Oct 21, 2009 at 10:18 AM, adambender <adamben...@gmail.com> wrote: >> >> This issue looks like it is directly related to >> http://issues.apache.org/jira/browse/WICKET-438 and the access of the >> lastModified header. Every time a URLResourceStream is constructed the >> lastModified time is requested at line 85 and the number of file handles >> goes up by one. The solution to the jira issue indicated that upgrading >> the >> version of linux fixed the problem but it doesnt seem to be the case with >> OS >> X or Red Hat Enterprise Linux... >> >> >> adambender wrote: >>> >>> I was able to distill the problem down to what I think is the core issue >>> here. >>> >>> When an AJAX Wicket page is rendered it contains a reference to two .js >>> files as Igor had mentioned, the Web URLs of these files look like this: >>> >>> <App Context >>> Root>/resources/org.apache.wicket.markup.html.WicketEventReference/wicket-event.js >>> <App Context >>> Root>/resources/org.apache.wicket.markup.html.WicketEventReference/wicket-ajax.js >>> >>> These requests are of course fielded by the Wicket filter which ends up >>> trying to load the resources using the UrlResourceStream. In order to >>> actually load these files Wicket gets the JAR URL for each file, >>> converts >>> them to a URIs and then passes them to the File constructor. The problem >>> is that the URI that is created is opaque - >>> http://www.docjar.com/docs/api/java/net/URI.html see here for a good >>> explanation in the case of wicket-event.js the URI string is like the >>> following : >>> >>> jar:file:/<absolute-path-tojar>/wicket-1.4.1.jar!/org/apache/wicket/markup/html/wicket-event.js >>> >>> It is similar for the case of wicket-ajax.js >>> >>> A quick glance at the File constructor shows that an opaque URL cannot >>> be >>> used to create a File as it is considered non-hierarchical. This of >>> course >>> leaves you with lots of requests to load this file, none of which can be >>> completed and results in a lot of open URL connections which can never >>> be >>> closed. >>> >>> I guess my question is, should this loading mechanism be working because >>> it doesnt seem like it could the way it is currently written? Is it >>> possible to configure how Wicket finds these files embedded in the jar? >>> Have I missed something? >>> >>> >>> Adam Bender-2 wrote: >>>> >>>> Thanks for the explanation I think that helps shed some light... The >>>> tests are actually JMeter tests driving load by emulating a web >>>> browser - the application the are testing is running in Deployment >>>> mode set up as though it were a production server. After a little more >>>> digging I have been able to determine that is only a problem on pages >>>> which use Ajax - and it looks like there is a related debug message >>>> coming from an exception handler regarding the wicket-event.js file >>>> not being accessible (URI is not hierarchical). This would actually >>>> explain why the problem only manifests when the JMeter tests are set >>>> to request embedded assets as wicket ajax pages embed requests for >>>> additional pieces of javascript - which in the case of wicket-event.js >>>> are causing exceptions to be thrown and the JVM bug you mentioned is >>>> probably preventing these resources from being cleaned up properly. >>>> >>>> Does that sound right? >>>> >>>> Adam >>>> >>>> >>>> On Oct 20, 2009, at 8:41 PM, Igor Vaynberg wrote: >>>> >>>>> when you are requesting an embedded resource wicket needs to stream >>>>> the file out of a jar, the way the jvm handles that is by creating a >>>>> jar url connection object that streams the file. unfortunately, there >>>>> is a bug in the jdk where the url connection does not have a close >>>>> method and so wicket or any other java app cannot release the >>>>> connection. this is addressed, afair, in jdk 7. >>>>> >>>>> i have many apps deployed in production and have not managed yet to >>>>> run out of the handles with the limit set about 4K. not sure why this >>>>> is different in your case. you mentioned "tests", are those unit tests >>>>> and is wicket there running in deployment mode? >>>>> >>>>> the resource watcher, which should be disabled, will cause the handles >>>>> to run out because it continuously monitors markup files for changes >>>>> (hot reloading in dev mode) and everytime it checks a markup file in a >>>>> jar it creates the url connection and leaks it. by default it is >>>>> disabled in deployment mode but if you manually set the poll frequency >>>>> in your settings it will be reenabled. >>>>> >>>>> -igor >>>>> >>>>> >>>>> On Tue, Oct 20, 2009 at 4:07 PM, Adam Bender <a...@magpieti.com> >>>>> wrote: >>>>>> We have run with a limit as high as 10,000 files and our tests can >>>>>> bring it >>>>>> to the limit in 20 minutes, but that still doesn't explain why so >>>>>> many >>>>>> copies of the jar are needed - and only when we are also requesting >>>>>> embedded >>>>>> assets... >>>>>> >>>>>> On Oct 20, 2009, at 5:04 PM, Major Péter wrote: >>>>>> >>>>>>> resolution -> solution... >>>>>>> Just set the ulimit in the initscript and run it with start-stop- >>>>>>> daemon, >>>>>>> it will make the problem disappear (but still there would be many >>>>>>> open >>>>>>> files...) >>>>>>> >>>>>>> Peter >>>>>>> >>>>>>> 2009-10-21 00:38 keltezéssel, Major Péter írta: >>>>>>>> >>>>>>>> Hi, >>>>>>>> >>>>>>>> we also had this issue, because (I think) we are running two >>>>>>>> different >>>>>>>> wicket application in only one glassfish domain. Our resolution >>>>>>>> was, >>>>>>>> that we are running now the glassfish domains with custom init >>>>>>>> scripts >>>>>>>> with ulimit settings. Maybe this will help for you. >>>>>>>> >>>>>>>> Best Regards, >>>>>>>> Peter >>>>>>>> >>>>>>>> 2009-10-21 00:14 keltezéssel, Martin Grigorov írta: >>>>>>>>> >>>>>>>>> Hi Adam, >>>>>>>>> >>>>>>>>> You may try to debug what is the problem with >>>>>>>>> https://wiki.sdn.sap.com/wiki/display/Java/JPicus >>>>>>>>> >>>>>>>>> El mar, 20-10-2009 a las 15:39 -0600, Adam Bender escribió: >>>>>>>>>> >>>>>>>>>> Greetings all, >>>>>>>>>> >>>>>>>>>> Recently I have been performance testing a Wicket application >>>>>>>>>> (1.4.1) >>>>>>>>>> and I >>>>>>>>>> am running into the dreaded Too Many Files Open issue. I have >>>>>>>>>> searched >>>>>>>>>> the >>>>>>>>>> mailing lists and most of the trouble around this issue seems >>>>>>>>>> to come >>>>>>>>>> from >>>>>>>>>> being in DEVELOPMENT mode so I made sure we were in DEPLOYMENT >>>>>>>>>> mode. >>>>>>>>>> When I >>>>>>>>>> run 'lsof -p xxxx | grep wicket-1.4.1.jar' I see over 1000 >>>>>>>>>> entries and >>>>>>>>>> it's >>>>>>>>>> growing monotonically. This seems really unusual - why would >>>>>>>>>> wicket >>>>>>>>>> need >>>>>>>>>> 1000 copies of this jar open? An additional bit of weirdness >>>>>>>>>> came up >>>>>>>>>> when >>>>>>>>>> our load tests stopped loading the embedded assets (css, js and >>>>>>>>>> images) >>>>>>>>>> in >>>>>>>>>> each page - this seemed to cap the number of lsof entries at >>>>>>>>>> 5... This >>>>>>>>>> is >>>>>>>>>> even weirder because our app serves these static items from httpd >>>>>>>>>> without >>>>>>>>>> tomcat ever knowing about them. How could our loading of >>>>>>>>>> embedded items >>>>>>>>>> really affect the number of file handles wicket needs? >>>>>>>>>> >>>>>>>>>> For completeness we are running this app on Red Hat Enterprise >>>>>>>>>> Linx 5 >>>>>>>>>> with >>>>>>>>>> Tomcat 6.0.20 and Java 1.6 >>>>>>>>>> >>>>>>>>>> Adam >>>>>>> >>>>>>> --------------------------------------------------------------------- >>>>>>> To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org >>>>>>> For additional commands, e-mail: users-h...@wicket.apache.org >>>>>>> >>>>>> >>>>>> >>>>>> --------------------------------------------------------------------- >>>>>> To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org >>>>>> For additional commands, e-mail: users-h...@wicket.apache.org >>>>>> >>>>>> >>>>> >>>>> --------------------------------------------------------------------- >>>>> To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org >>>>> For additional commands, e-mail: users-h...@wicket.apache.org >>>>> >>>> >>>> >>>> --------------------------------------------------------------------- >>>> To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org >>>> For additional commands, e-mail: users-h...@wicket.apache.org >>>> >>>> >>>> >>> >>> >> >> -- >> View this message in context: >> http://www.nabble.com/Too-Many-Files-Wicket-1.4.1-tp25983047p25996646.html >> Sent from the Wicket - User mailing list archive at Nabble.com. >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org >> For additional commands, e-mail: users-h...@wicket.apache.org >> >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org > For additional commands, e-mail: users-h...@wicket.apache.org > > > -- View this message in context: http://www.nabble.com/Too-Many-Files-Wicket-1.4.1-tp25983047p25999669.html Sent from the Wicket - User mailing list archive at Nabble.com. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org For additional commands, e-mail: users-h...@wicket.apache.org
