So the patch did help?

I too have observed this problem but it was at the moment less of a problem than other heap eaters, now this is next in line. We have added a script which automatically restarts the server when repeated OOME occurs and are down to a couple of times per week without the patch. But still, who wouldn't want to see months of uptime...

// Daniel
jalbum.net


On 2008-06-10, at 11:29, Stefan Fußenegger wrote:


Hi Igor,

Thanks for your quick reply and the patch, sorry for not searching the
mailinglist only but not JIRA.

Your patch was for 1.4, I applied it to 1.3.3, created a quickstart
including JUnit test and attached it to the JIRA issue. Hope this fix gets into the next maintenance release. I am to lazy to create a properly patched
jar and a MVN repo for my team right now ;)

Regards, Stefan



igor.vaynberg wrote:

try applying this patch and see if it helps

https://issues.apache.org/jira/browse/WICKET-1667

-igor

On Mon, Jun 9, 2008 at 8:11 AM, Stefan Fußenegger
<[EMAIL PROTECTED]> wrote:

I am just analysing a heap dump (god bless the
-XX:+HeapDumpOnOutOfMemoryError flag) of a recent application cache due
to
an OutOfMemoryError ("GC overhead limit exceeded" to be precise). Using
jhat, the "175456 instances of class
org.apache.wicket.util.concurrent.ConcurrentHashMap$Entry" immediately
got
my attention. While looking through the 107 instance of
ConcurrentHashMap, I
found one *really* big one: Localizer.cache has a hash table length of 262144, each of its 32 segments with about 5300 entries, where a hash key
is
a string, sometimes longer than 500 charactes, similar to (see
Localizer.getCacheKey(String,Component)):

fooTitle.bar- org.apache.wicket.markup.html.link.BookmarkablePageLink:fooLink- org.apache.wicket.markup.html.panel.Fragment:track- org.apache.wicket.markup.html.list.ListItem:14- my.company.FooListPanel$1:fooList-my.company.FooListPanel:foos- org.apache.wicket.markup.html.list.ListItem:0- my.company.BarListPanel$1:bars-my.company.FooListPanel:panel- my.company.boxes.BodyBox:2- org.apache.wicket.markup.repeater.RepeatingView:body- my.company.layout.Border:border-my.company.pages.music.FoobarPage: 43-de-null

Those numbers pretty much convinced me: The localizer cache has blown
away
my application.

Looking at this hash keys, I suspect the following problem: those strings
are constructed from the "position" of a localized String on a page,
which
is quite a bad thing if you use nested list views or repeating views to construct your page. For instance, I have a panel with a long (pageable) list of entries, might be > 5000 entries which might appear on various positions in a repeating view I use as a container for most of my pages. Let's say there are 5 possible positions, this would cause 2500 thousand
cached entries, each with a key of 300+ characters plus some more
characters
for the cached message - feel free to do the maths. From a quick estimate
I'd say: No wonder, this has blown away my app.

As a quick fix, I'd suggest to regularly clear the localizer cache, use a more sophisticated cache (that expires old entries once in a while!!) or
to
disable the cache completely. However, don't try to overwrite
Localizer.newCache() and clear the cache regularly: clearCache() will
replace your cache with a ConcurrentHashMap (not using
Localizer.newCache()). However, quite unlikely, that this will happen as newCache() is private anyway ;) I am going to add some code to clear the
cache regularly.

Best regards, Stefan

PS: I'll also create a JIRA issue, but I am really short on time right
now.

-----
-------
Stefan Fußenegger
http://talk-on-tech.blogspot.com // looking for a nicer domain ;)
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-----
-------
Stefan Fußenegger
http://talk-on-tech.blogspot.com // looking for a nicer domain ;)
--
View this message in context: 
http://www.nabble.com/Localizer-cache-with-150.000%2B-entries-causing-OutOfMemory-tp17734931p17751273.html
Sent from the Wicket - User mailing list archive at Nabble.com.


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