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From bugzi...@apache.org
Subject DO NOT REPLY [Bug 35507] New: - Light weight Threads locked and seen in core dump.
Date Sun, 26 Jun 2005 05:08:51 GMT
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http://issues.apache.org/bugzilla/show_bug.cgi?id=35507

           Summary: Light  weight  Threads locked and seen in core dump.
           Product: Tomcat 5
           Version: 5.5.7
          Platform: Sun
        OS/Version: SunOS
            Status: NEW
          Severity: critical
          Priority: P1
         Component: Unknown
        AssignedTo: tomcat-dev@jakarta.apache.org
        ReportedBy: dnkumar1@rediffmail.com


We have Tomcat 5.5.7 Server configured in SunOS 5.8 box. Our web service
application is deployed in tomcat.
This application is invoked using a Service URL (SOAP over http) and AXIS.

Problem Description : 
Once in a while (does not occur often) the tomcat server responds very slowly
and consumes more CPU. 
when this happens we see lot of internal threads of tomcat which are active and
one of the light weight thread takes the major share of CPU.
After a while the server hangs (responds slowly) and will finally stops dumping
the java core dump in catalina.out file.

We were able monitor this for our 2 servers. One of the server stopped and we
found the core dump in catalina.out

Second server was responding very slowly and was taking more CPU. 

SUN has asked us to change the Garbage collection (GC) method.
This helps to answer the Server pause and sudden increase in CPU usage by one of
the light weight process (JV thread for GC) 

But Java core dump in generated when server came down shows lot many threads 

Some of them are locked and stacktrace is similar to - 
         "http-8082-Processor350" daemon prio=5 tid=0x00a64978 nid=0x24b68 in
Object.wait() [5b801000..5b8019c0]
             at java.lang.Object.wait(Native Method)
             at java.lang.Object.wait(Object.java:429)
             at
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:656)
             - locked <0x75e9ee28> (a
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable)
             at java.lang.Thread.run(Thread.java:534)

Some of them have following stacktrace - 

    "http-8080-Processor125" daemon prio=5 tid=0x0135e148 nid=0x4ca32 runnable
[69f00000..69f019c0]
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.read(SocketInputStream.java:129)
        at java.io.BufferedInputStream.fill(BufferedInputStream.java:183)
        at java.io.BufferedInputStream.read1(BufferedInputStream.java:222)
        at java.io.BufferedInputStream.read(BufferedInputStream.java:277)
        - locked <0x8cc5e478> (a java.io.BufferedInputStream)
        at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:756)
        at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:711)
        at
sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:635)
        - locked <0x8cc578a0> (a sun.net.www.protocol.http.HttpURLConnection)
        at
com.wfb.ivs.image.persistence.connection.DEXConnector.read(DEXConnector.java:422)

 
We dont know why these threads are locked..Is this a problem with tomcat ?
Can any one help us to figure this out.

Thanks
Naveen.

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