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From Toby Lazar <tla...@capitaltg.com>
Subject Re: closing hbase resources for webapp
Date Tue, 04 Mar 2014 02:46:49 GMT
After hitting the jsp once and then reloading the app, I ran Find leaks
through the manager application at http://localhost:8080/manager/html and
get this:

   The following web applications were stopped (reloaded, undeployed), but their
   classes from previous runs are still loaded in memory, thus causing a memory
   leak (use a profiler to confirm):
   /dynam

The name of the web app context is dynam.  Each time I repeat, I get
an extra /dynam line, as expected.  Additionally, each time I reload
the context catalina.out shows:

   SEVERE: The web application [/dynam] appears to have started a thread
named
   [IPC Client (1622444498) connection to hb02/192.168.200.102:60020 from
tslazar]
   but has failed to stop it. This is very likely to create a memory leak.

Is there a ZooKeeper method I should call to shutdown a thread?  I added a
finally block though that doesn't change the behavior.


On Mon, Mar 3, 2014 at 8:55 PM, Ted Yu <yuzhihong@gmail.com> wrote:

> bq. Tomcat detects that I may have a memory leak
>
> Can you show us the warning from Tomcat.
>
> w.r.t. the snippet you posted: the two close() calls should be enclosed in
> finally block.
>
>
> On Mon, Mar 3, 2014 at 1:21 PM, Toby Lazar <tlazar@capitaltg.com> wrote:
>
> > I am working on an HBase webapp and Tomcat is telling me I have a memory
> > leak, which I have confirmed, but I'm not sure how to fix it.  I've
> reduced
> > my app to a single jsp that calls a single method (both are included
> below
> > since they are short).  After I reload my application, Tomcat detects
> that
> > I may have a memory leak, leading me to think I should be doing something
> > else when closing an HConnection.  I tried the deprecated
> > HConnectionManager.deleteConnection(config) without any luck.
> >
> > I am using Hadoop 2.2/HBase 0.96 client jars and running it on Tomcat
> > 7.0.47/JVM 1.7.0_45 on CentOS 6.5.
> >
> > Any ideas what I'm missing or how to work around this?
> >
> > Thanks!
> >
> > Toby
> >
> >
> >
> > JSP is:
> >
> > <%@page import="foobar.Test"%>
> > <%@ page language="java" contentType="text/html; charset=UTF-8"
> >     pageEncoding="UTF-8"%>
> > <%out.println(Test.hello()); %>
> >
> > Java method in the Test class is:
> >
> > public static String hello() throws IOException{
> >  Configuration config = HBaseConfiguration.create();
> > HConnection connection = HConnectionManager.createConnection(config);
> > HTableInterface table = connection.getTable("sometable");
> > table.close();
> > connection.close();
> > return "hellosay";
> >  }
> >
> >
> >
> > *******************************
> >   Toby Lazar
> >   Capital Technology Group
> >   Email: tlazar@capitaltg.com
> >   Mobile: 646-469-5865
> > *******************************
> >
>

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