Skip to main content

Java com.sun.net.httpserver. HttpServer OutOfMemory Issue

We had to extract text out of documents that people were uploading to the site so we can index them. As this was going to be just a text extraction services I didnt wanted to go for some full blown tomcat server so wrote a quick http server using java

        this.httpServer = HttpServer.create(addr, 0);
        HttpContext context = this.httpServer.createContext("/", new DocumentProcessHandler());
        this.httpThreadPool = Executors.newFixedThreadPool(this.noOfThreads);
        this.httpServer.setExecutor(this.httpThreadPool);
        context.getFilters().add(new HttpParameterFilter());
        this.httpServer.start();
Not adding all code for brevity. 

After being live for 2-3 days the process started crashing and it was a regular pattern. I added -verbose:gc -XX:+HeapDumpOnOutOfMemoryError to the startup script and had a crash dump after 3 days. Using eclipse Memory Analyzer and using Histogram to look at the heap dump revealed that we had 90K HttpConnection objects. wow that looks for sure like a leak.



I tried everything from closing the exchange, responseBody as shown below but the connections would remain.

    class DocumentProcessHandler implements HttpHandler {
        @SuppressWarnings("unchecked")
        public void handle(HttpExchange exchange) throws IOException {
                PrintWriter responseBody = new PrintWriter(exchange.getResponseBody());

                try {
..........code removed for brevity of post....................
                } catch (Throwable t) {
                    logger.error(t);
                    throw new IOException(t);
                } finally {
                    responseBody.flush();
                    responseBody.close();
                    exchange.close();
                }
        }
    }

To prove my theory I send few http requests and did jmap -histo:live 16315 |grep http and keep on seeing the http connections would increase after every requests.
This is definitely a bug in the HttpServer code so use it only for demos and not for production use. I saw that lots of other people are also facing same issues and sun wont agree that its a bug so I am again moving back to tomcat :).


 http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6563368
http://forums.sun.com/thread.jspa?threadID=5380631
http://www.experts-exchange.com/Programming/Languages/Java/Q_24416845.html

Comments

  1. AnonymousJuly 8, 2010 at 1:05 PM

    I find out if the HTTP GET request has some extra bytes after the last 0xd 0xa in the HTTP header, it could lead to this leak as the HttpConnection is not added to "idleConnections" in sun.net.httpserver.ServerImpl

    ReplyDelete
  2. Drew NoakesFebruary 5, 2013 at 8:19 AM

    Another relevant bug report: http://bugs.sun.com/view_bug.do;?bug_id=6946825

    ReplyDelete

Post a Comment

Popular posts from this blog

Haproxy and tomcat JSESSIONID

One of the biggest problems I have been trying to solve at our startup is to put our tomcat nodes in HA mode. Right now if a customer comes, he lands on to a node and remains there forever. This has two major issues: 1) We have to overprovision each node with ability to handle worse case capacity. 2) If two or three high profile customers lands on to same node then we need to move them manually. 3) We need to cut over new nodes and we already have over 100+ nodes.  Its a pain managing these nodes and I waste lot of my time in chasing node specific issues. I loath when I know I have to chase this env issue. I really hate human intervention as if it were up to me I would just automate thing and just enjoy the fruits of automation and spend quality time on major issues rather than mundane task,call me lazy but thats a good quality. So Finally now I am at a stage where I can put nodes behing HAProxy in QA env. today we were testing the HA config and first problem I immediately
Post a Comment
Read more

Adding Jitter to cache layer

Thundering herd is an issue common to webapp that rely on heavy caching where if lots of items expire at the same time due to a server restart or temporal event, then suddenly lots of calls will go to database at same time. This can even bring down the database in extreme cases. I wont go into much detail but the app need to do two things solve this issue. 1) Add consistent hashing to cache layer : This way when a memcache server is added/removed from the pool, entire cache is not invalidated.  We use memcahe from both python and Java layer and I still have to find a consistent caching solution that is portable across both languages. hash_ring and spymemcached both use different points for server so need to read/test more. 2) Add a jitter to cache or randomise the expiry time: We expire long term cache  records every 8 hours after that key was added and short term cache expiry is 2 hours. As our customers usually comes to work in morning and access the cloud file server it can happe
Post a Comment
Read more

Spring 3.2 quartz 2.1 Jobs added with no trigger must be durable.

I am trying to enable HA on nodes and in that process I found that in a two test node setup a job that has a frequency of 10 sec was running into deadlock. So I tried upgrading from Quartz 1.8 to 2.1 by following the migration guide but I ran into an exception that says "Jobs added with no trigger must be durable.". After looking into spring and Quartz code I figured out that now Quartz is more strict and earlier the scheduler.addJob had a replace parameter which if passed to true would skip the durable check, in latest quartz this is fixed but spring hasnt caught up to this. So what do you do, well I jsut inherited the factory and set durability to true and use that public class DurableJobDetailFactoryBean extends JobDetailFactoryBean {     public DurableJobDetailFactoryBean() {         setDurability(true);     } } and used this instead of JobDetailFactoryBean in the spring bean definition     <bean id="restoreJob" class="com.xxx.infrastructure.quar
7 comments
Read more