[xwiki-users] XWiki going out of resources
Hi XWiki users, fwiw I just want to share my experiences and observations with XWiki instance running out of memory. I was having a hard time to track this down but in the end I could successfully isolate the problem. For quite some time my XWiki instance was getting unresponsive to requests sooner or later. The Wiki was hosted on a VirtualBox VM and in most cases the VM guest was just freezing and needed to be restarted leaving no usable traces in the logs. In some cases I even found JVM crash reports so I first checked different JVMs and VirtualBox versions (PUEL and OSE licences). I had no success with this approach and so I moved the XWiki directly to a host environment (Ubuntu 10.10). I added Server instrumentation (VisualVM) but still the wiki got down after a while. Surprisingly the system was hanging although in many cases there was even enough memory available (I checked different VM settings up to 4GB). Finally a VisualVM thread dump showed what happened: When the robots came visiting my service they query a large number of pages and among them was one user-url: .../XWiki/someUser which ran into an infinite looping condition when rendering the page. I don't know how this could happen but as a result the whole memory was consumed and partly released afterwards so it seemed that there is still enough space available. Once this happened however the Webserver needed to be restarted because it wasn't responsive any more. Since I have deleted this user account everything is running ok for a couple of days now - I still have to move the service back into the VirtualBox guest VM. What puzzles me finally that its possible that one single request can kill the service by going into an infinte rendering loop. I would have thought that at some level there is a depth limit to prevent such conditions. Hope these observations help someone though .... enjoy Andreas
On 01/03/2011 12:38 PM, Andreas Hahn wrote:
Hi XWiki users,
fwiw I just want to share my experiences and observations with XWiki instance running out of memory.
I was having a hard time to track this down but in the end I could successfully isolate the problem. For quite some time my XWiki instance was getting unresponsive to requests sooner or later.
The Wiki was hosted on a VirtualBox VM and in most cases the VM guest was just freezing and needed to be restarted leaving no usable traces in the logs. In some cases I even found JVM crash reports so I first checked different JVMs and VirtualBox versions (PUEL and OSE licences).
I had no success with this approach and so I moved the XWiki directly to a host environment (Ubuntu 10.10). I added Server instrumentation (VisualVM) but still the wiki got down after a while. Surprisingly the system was hanging although in many cases there was even enough memory available (I checked different VM settings up to 4GB). Finally a VisualVM thread dump showed what happened: When the robots came visiting my service they query a large number of pages and among them was one user-url: .../XWiki/someUser which ran into an infinite looping condition when rendering the page. I don't know how this could happen but as a result the whole memory was consumed and partly released afterwards so it seemed that there is still enough space available. Once this happened however the Webserver needed to be restarted because it wasn't responsive any more. Since I have deleted this user account everything is running ok for a couple of days now - I still have to move the service back into the VirtualBox guest VM.
What puzzles me finally that its possible that one single request can kill the service by going into an infinte rendering loop. I would have thought that at some level there is a depth limit to prevent such conditions.
Normally, there are recursion checks in different places, like velocity macros can be nested to at most 20 levels (100 in 3.0). What would help is exporting the user profile as XAR and uploading it somewhere so that we can see what's causing this specific problem.
Hope these observations help someone though ....
-- Sergiu Dumitriu http://purl.org/net/sergiu/
Am 03.01.2011 13:21, schrieb Sergiu Dumitriu:
On 01/03/2011 12:38 PM, Andreas Hahn wrote:
Hi XWiki users,
fwiw I just want to share my experiences and observations with XWiki instance running out of memory.
I was having a hard time to track this down but in the end I could successfully isolate the problem. For quite some time my XWiki instance was getting unresponsive to requests sooner or later.
The Wiki was hosted on a VirtualBox VM and in most cases the VM guest was just freezing and needed to be restarted leaving no usable traces in the logs. In some cases I even found JVM crash reports so I first checked different JVMs and VirtualBox versions (PUEL and OSE licences).
I had no success with this approach and so I moved the XWiki directly to a host environment (Ubuntu 10.10). I added Server instrumentation (VisualVM) but still the wiki got down after a while. Surprisingly the system was hanging although in many cases there was even enough memory available (I checked different VM settings up to 4GB). Finally a VisualVM thread dump showed what happened: When the robots came visiting my service they query a large number of pages and among them was one user-url: .../XWiki/someUser which ran into an infinite looping condition when rendering the page. I don't know how this could happen but as a result the whole memory was consumed and partly released afterwards so it seemed that there is still enough space available. Once this happened however the Webserver needed to be restarted because it wasn't responsive any more. Since I have deleted this user account everything is running ok for a couple of days now - I still have to move the service back into the VirtualBox guest VM.
What puzzles me finally that its possible that one single request can kill the service by going into an infinte rendering loop. I would have thought that at some level there is a depth limit to prevent such conditions. Normally, there are recursion checks in different places, like velocity macros can be nested to at most 20 levels (100 in 3.0). What would help is exporting the user profile as XAR and uploading it somewhere so that we can see what's causing this specific problem.
Ok, thanks for your support offer. I'll see if I can restore the old user profile. I've created a new one with the same name in the meantime.
Hope these observations help someone though ....
This problem seems to strike back on me. Whenever I open the users page .../XWiki/aha it sends the garbage collector to infinity - restarting Tomcat is the only help. However its an older wiki: XWiki Enterprise 2.3-milestone-1.27899 This is the .xar: https://docs.google.com/leaf?id=0B05JH-hYx5XINjkyNzBlNjAtODkyYy00MWUxLTlkNWQ... Thanks for your support Andreas -- View this message in context: http://xwiki.475771.n2.nabble.com/XWiki-going-out-of-resources-tp5885402p619... Sent from the XWiki- Users mailing list archive at Nabble.com.
Hi Andreas, On Mar 23, 2011, at 10:05 AM, Andreas Hahn wrote:
This problem seems to strike back on me. Whenever I open the users page .../XWiki/aha it sends the garbage collector to infinity - restarting Tomcat is the only help. However its an older wiki: XWiki Enterprise 2.3-milestone-1.27899
This is the .xar:
https://docs.google.com/leaf?id=0B05JH-hYx5XINjkyNzBlNjAtODkyYy00MWUxLTlkNWQ...
Thanks for your support
I don't know what the problem is but do you have the same issue with XE 2.7.1 or XE 3.0M3? (would be good to know if there's something to fix) Thanks -Vincent PS: Note that the strategy for xwiki developers is to support only the last 2 versions (ie 2.7.x and 3.0 as of now). See http://www.xwiki.org/xwiki/bin/view/Main/Support (I've just added the info box) That said, you may be lucky and find someone to help you with your specific problem on a 2.3M1 release.
Andreas
Am 23.03.2011 10:31, schrieb Vincent Massol:
Hi Andreas,
On Mar 23, 2011, at 10:05 AM, Andreas Hahn wrote:
This problem seems to strike back on me. Whenever I open the users page .../XWiki/aha it sends the garbage collector to infinity - restarting Tomcat is the only help. However its an older wiki: XWiki Enterprise 2.3-milestone-1.27899
This is the .xar:
https://docs.google.com/leaf?id=0B05JH-hYx5XINjkyNzBlNjAtODkyYy00MWUxLTlkNWQ...
Thanks for your support I don't know what the problem is but do you have the same issue with XE 2.7.1 or XE 3.0M3? (would be good to know if there's something to fix)
Thanks -Vincent
PS: Note that the strategy for xwiki developers is to support only the last 2 versions (ie 2.7.x and 3.0 as of now). See http://www.xwiki.org/xwiki/bin/view/Main/Support (I've just added the info box) That said, you may be lucky and find someone to help you with your specific problem on a 2.3M1 release.
I understand that. However in that instance I did some changes to the *.cfg and thus I hoped to avoid trouble by postponing the migration ... thanks Andreas
Andreas
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participants (3)
-
Andreas Hahn -
Sergiu Dumitriu -
Vincent Massol