Yep, 5.0.28, sorry:) Jamey
-----Original Message----- From: Filip Hanik - Dev Lists [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 01, 2006 4:48 PM To: Tomcat Developers List Subject: Re: ArrayIndexOutOfBoundsException in ResourceCache.java if you can create a test case, great, if not, a patch would be nice with your bug submission. I believe you meant version 5.0.28, not 4.xx.x. Filip James Courtney wrote: > Thanks Filip, > I believe the threads causing the condition are the connector > threads as we have 200 or so of them configured for handling requests > of which most are for static content which apparently comes from the > ResourceCache via ProxyDirContext and Mapper. We do not "own" these > threads as they are created and managed by the connector for handling > requests. The exception is occuring when looking up a static piece of > content. ProxyDirContext manages the ResourceCache and synchonizes on > it whenever it modifies it using allocate and load and also unload. > It does not synchronize on it when it uses the lookup method which has > the problem I mentioned below. An alternative solution would be for > ProxyDirContext to synchronized on the cache when performing the > lookup but that might introduce more overhead than the read-copy > method I suggested initially. > > I will attempt to file a bug on this and suggest a test case. We're > seeing this in our environment because we have a static content base > of > 30+ MB consisting of 8000-10000 static files all being accessed at > regular intervals by 8000+ clients. This causes a lot of "churn" in > the ResourceCache I suspect and aggrivates the exception we see. One > might be able to reproduce this by explicitly reducing the max size of > the cache on the Context and using a smaller number of files whose > total size still far exceeds the cache maximum size set. A sufficient > number of clients would still be required to trigger the race > condition. In short it's probably a PITA to reproduce but I'll suggest what I can. > > How explicit a configuration do you guys need from me for a test case? > I'll try and reproduce it on vanilla Tomcat 4.0.28 (non-embedded) as > I'd think that'd be just as possible to do and more generally > relevant. If I can then I'll try and do it using as simple/minimal a > config as possible but we'll see:) > > Thanks again. > > Jamey > > > > -----Original Message----- > From: Filip Hanik - Dev Lists [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 01, 2006 3:21 PM > To: Tomcat Developers List > Subject: Re: ArrayIndexOutOfBoundsException in ResourceCache.java > > if you are running it embedded, what threads are causing the race > condition, if it is one of your threads, you can avoid it. > otherwise, if you have a test case for us, submit it to bugzilla, and > we will be happy to consider it for the next 5.0.x release > > Filip > > James Courtney wrote: > >> I'm pretty regularly seeing the following error in my embedded Tomcat >> (5.0.28) connector. It appears to occur as a result of one thread >> entering the ResourceCache.lookup(String name) method and getting the >> index of an element in the cache using the find method. Before this >> thread can access the element at that index the cache array is >> modified by a second thread and the index is now outside the bounds >> of >> > the array. > >> A basic race condition. I've noticed that I can configure my Context >> (StandardContext) to increase the max cache size which seems to help >> quite a bit with this problem. Is this the recommended solution or >> should a code change also be considered to alleviate this problem? I >> would suggest that the ResourceCache.lookup method should create a >> reference to the current cache which it should use rather than >> working >> > > >> on the global cache reference which may change. Something like this: >> >> /* current code, ResourceCache.java line 286 */ CacheEntry cacheEntry >> = null; ... >> int pos = find(cache, name); >> /* ArrayIndexOutOfBoundsException occurs when backing array modified >> between these lines */ if ((pos != -1) && >> (name.equals(cache[pos].name))) { >> cacheEntry = cache[pos]; >> } >> >> /* new code */ >> CacheEntry cacheEntry = null; >> CacheEntry[] currentCache = cache; >> ... >> int pos = find(currentCache, name); >> if ((pos != -1) && (name.equals(currentCache[pos].name))) { >> cacheEntry = currentCache[pos]; >> } >> >> Thanks in advance for your help! >> >> James Courtney >> >> >> >> ****************************** >> ** The original stack trace ** >> ****************************** >> >> 2005-11-28 15:09:01: ERROR An exception or error occurred in the >> container during the request processing >> java.lang.ArrayIndexOutOfBoundsException: 4868 >> at >> >> > org.apache.naming.resources.ResourceCache.lookup(ResourceCache.java:28 > 8) > >> at >> >> > org.apache.naming.resources.ProxyDirContext.cacheLookup(ProxyDirContext. > >> java:1393) >> at >> >> > org.apache.naming.resources.ProxyDirContext.lookup(ProxyDirContext.java: > >> 279) >> at >> org.apache.tomcat.util.http.mapper.Mapper.internalMapWrapper(Mapper.j >> a >> va >> :775) >> at >> org.apache.tomcat.util.http.mapper.Mapper.internalMap(Mapper.java:621) >> at >> org.apache.tomcat.util.http.mapper.Mapper.map(Mapper.java:511) >> at >> org.apache.coyote.tomcat5.CoyoteAdapter.postParseRequest(CoyoteAdapte >> r >> .j >> ava:279) >> at >> >> > org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:158 > ) > >> at >> org.apache.coyote.http11.Http11Processor.process(Http11Processor.java: >> 79 >> 9) >> at >> org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.proce >> s >> sC >> onnection(Http11Protocol.java:705) >> at >> org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java: >> 57 >> 7) >> at >> org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadP >> o >> ol >> .java:683) >> at java.lang.Thread.run(Thread.java:534) >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [EMAIL PROTECTED] For >> additional commands, e-mail: [EMAIL PROTECTED] >> >> >> >> >> > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] For > additional commands, e-mail: [EMAIL PROTECTED] > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] For > additional commands, e-mail: [EMAIL PROTECTED] > > > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
