Operating System - HP-UX
1752268
Members
4953
Online
108786
Solutions
Forums
Categories
Company
Local Language
юдл
back
Forums
Discussions
Forums
- Data Protection and Retention
- Entry Storage Systems
- Legacy
- Midrange and Enterprise Storage
- Storage Networking
- HPE Nimble Storage
Discussions
Discussions
Discussions
Forums
Forums
Discussions
юдл
back
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
- BladeSystem Infrastructure and Application Solutions
- Appliance Servers
- Alpha Servers
- BackOffice Products
- Internet Products
- HPE 9000 and HPE e3000 Servers
- Networking
- Netservers
- Secure OS Software for Linux
- Server Management (Insight Manager 7)
- Windows Server 2003
- Operating System - Tru64 Unix
- ProLiant Deployment and Provisioning
- Linux-Based Community / Regional
- Microsoft System Center Integration
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Blogs
Information
Community
Resources
Community Language
Language
Forums
Blogs
Topic Options
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО05-31-2007 06:24 PM
тАО05-31-2007 06:24 PM
Tomcat
Would syslog tell me if a Tomcat seesion hangs ? or where can I go to see it.
3 REPLIES 3
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО05-31-2007 07:27 PM
тАО05-31-2007 07:27 PM
Re: Tomcat
Shalom,
syslog would probably not tell you if a tomcat session hung. You might look for a core dump in the home or application directory or at the number of tomcat or java sessions in ps -ef
tomcat has a log file of sorts which I've not found helpful, but it does exist and there may be some evidence in there.
SEP
syslog would probably not tell you if a tomcat session hung. You might look for a core dump in the home or application directory or at the number of tomcat or java sessions in ps -ef
tomcat has a log file of sorts which I've not found helpful, but it does exist and there may be some evidence in there.
SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО05-31-2007 07:50 PM
тАО05-31-2007 07:50 PM
Re: Tomcat
First you'll have to define what you mean with "Tomcat session".
Do you mean a running Tomcat process, as seen by the operating system of the server?
If the process becomes unresponsive, it may be in a tight loop doing something repeatedly. In this case, the OS does not see anything wrong: the process is busy doing something... it just happens to be something useless.
If you're using Sun's JVM, sending a "kill -QUIT" to the Java process running Tomcat will cause the JVM to print out a "thread dump" which tells you exactly what the process was doing at the moment. The thread dump goes to the standard output of the Java process... which might be redirected to some log file somewhere, or even /dev/null. So you might have to examine or tweak your set-up a bit to find out where the thread dump goes and catch it.
Or if the process is not consuming any CPU time, it might be waiting for some I/O operation. If your disk is failing or some network resource your program is using is unreachable, this might be the reason. Disk errors usually cause a lot of messages to be sent to the syslog and kernel message buffer (use the command "dmesg" to see it).
Some years ago, we had lots of problems with old Java versions and urlConnect methods, because there wasn't any way to specify a timeout for the connection. Analyzing the thread dumps helped to see what was going on.
Or do you mean a "Tomcat session" as seen by the client with a web browser?
The HTTP protocol does not have a concept of sessions. If an application wishes to have a concept of sessions, it must keep track of the users and their sessions in some way. Common methods are using cookies or embedding some session-identifying information into the URLs.
If a client sees a session hanging, the first thing to examine is: what happens at the Tomcat server end? Has some network problem prevented the client's requests from reaching the server, or has something in the client's request caused the server to become stuck (see above)? The access logs might help to identify whether it is a network problem or not.
MK
Do you mean a running Tomcat process, as seen by the operating system of the server?
If the process becomes unresponsive, it may be in a tight loop doing something repeatedly. In this case, the OS does not see anything wrong: the process is busy doing something... it just happens to be something useless.
If you're using Sun's JVM, sending a "kill -QUIT" to the Java process running Tomcat will cause the JVM to print out a "thread dump" which tells you exactly what the process was doing at the moment. The thread dump goes to the standard output of the Java process... which might be redirected to some log file somewhere, or even /dev/null. So you might have to examine or tweak your set-up a bit to find out where the thread dump goes and catch it.
Or if the process is not consuming any CPU time, it might be waiting for some I/O operation. If your disk is failing or some network resource your program is using is unreachable, this might be the reason. Disk errors usually cause a lot of messages to be sent to the syslog and kernel message buffer (use the command "dmesg" to see it).
Some years ago, we had lots of problems with old Java versions and urlConnect methods, because there wasn't any way to specify a timeout for the connection. Analyzing the thread dumps helped to see what was going on.
Or do you mean a "Tomcat session" as seen by the client with a web browser?
The HTTP protocol does not have a concept of sessions. If an application wishes to have a concept of sessions, it must keep track of the users and their sessions in some way. Common methods are using cookies or embedding some session-identifying information into the URLs.
If a client sees a session hanging, the first thing to examine is: what happens at the Tomcat server end? Has some network problem prevented the client's requests from reaching the server, or has something in the client's request caused the server to become stuck (see above)? The access logs might help to identify whether it is a network problem or not.
MK
MK
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО05-31-2007 08:01 PM
тАО05-31-2007 08:01 PM
Re: Tomcat
Sorry it was a Tomcat Process... I guess by what your saying is that is very dificult to find a hung Tomcat process.
I would think that when a process is in a loop it will consume lots of cpu.
I would think that when a process is in a loop it will consume lots of cpu.
The opinions expressed above are the personal opinions of the authors, not of Hewlett Packard Enterprise. By using this site, you accept the Terms of Use and Rules of Participation.
News and Events
Support
© Copyright 2024 Hewlett Packard Enterprise Development LP