ASG
IBM
Zystems
Cressida
Icon
Netflexity
 
  MQSeries.net
Search  Search       Tech Exchange      Education      Certifications      Library      Info Center      SupportPacs      LinkedIn  Search  Search                                                                   FAQ  FAQ   Usergroups  Usergroups
 
Register  ::  Log in Log in to check your private messages
 
RSS Feed - WebSphere MQ Support RSS Feed - Message Broker Support

MQSeries.net Forum IndexWebSphere Application ServerDoes Garbage Collection (GC) trigger JVM restart?

Post new topicReply to topic
Does Garbage Collection (GC) trigger JVM restart? View previous topic :: View next topic
Author Message
EricL
PostPosted: Wed Apr 04, 2018 11:48 am Post subject: Does Garbage Collection (GC) trigger JVM restart? Reply with quote

Acolyte

Joined: 10 Oct 2014
Posts: 66

Hi,

1. We have a cluster (with 2 JVMs) created on Websphere Application Server(V8.0.0.12)
2. Yesterday morning, one of the JVMs (call it JVM2) got OutOfMemory(OOM) error started at [April/3/2018 0:18:55:819 AM], the error keep on repeating again and again, until [April/3/2018 9:02:01:438 AM], the last OOM error message was logged, it lasted about 9 hours.
3. After last OutOfMemory(OOM) error message logged at about [April/3/2018 9:02:01:438 AM], we noticed JVM started rebooting:
....
...
[April/3/2018 9:02:18:051 EDT] 00000000 ManagerAdmin I TRAS0017I: The startup trace state is *=info:org.apache.struts.tiles.commands.TilesPreProcessor=off.
...
....

When rebooting done, everything backed to normal....

Question now is: What has been triggered the JVM rebooting? Was it GC?

We've been searching hard trying to find any evidence to prove it is GC triggered the JVM restart, but all logs: systemout.log and FFDC log didn't have any info to support it, so again, question is: does GC trigger JVM restart?

Thanks,
Eric
Back to top
View user's profile Send private message
fjb_saper
PostPosted: Wed Apr 04, 2018 6:41 pm Post subject: Reply with quote

Grand Poobah

Joined: 18 Nov 2003
Posts: 19629
Location: LI,NY

I don't think so. If I had to take a guess I'd say the OOM error triggered it.
If after GC you still get an OOM error there is nothing the JVM can do but reboot. It is also the sign of a probable memory leak. Find it!, Plug it!
_________________
MQ & Broker admin
Back to top
View user's profile Send private message Send e-mail
EricL
PostPosted: Thu Apr 05, 2018 9:59 am Post subject: Reply with quote

Acolyte

Joined: 10 Oct 2014
Posts: 66

Thanks Grand.

Think this is the tricky part of the situation, we noticed JVM restarted, but can not find out what caused it, could be either OOM error or GC, or something else, we just want to get some evidence to confirm it, regardless whatever cause...

Eric
Back to top
View user's profile Send private message
rekarm01
PostPosted: Thu Apr 05, 2018 4:18 pm Post subject: Reply with quote

Grand Master

Joined: 25 Jun 2008
Posts: 1297

Acolyte wrote:
Thanks Grand.

A user's name is different from a user's rank.

Acolyte wrote:
we noticed JVM restarted, but can not find out what caused it, could be either OOM error or GC, or something else ...

By the time a JVM throws an OutOfMemoryError, it has already completed garbage collection.
Back to top
View user's profile Send private message
EricL
PostPosted: Mon Apr 09, 2018 4:01 pm Post subject: Reply with quote

Acolyte

Joined: 10 Oct 2014
Posts: 66

Hi,

Just an update, it looks like OutOfMemory caused JVM restart, got logs shown:

1. OOM error today started at: [April/9/2018 0:34:08:084 am], and
2. Last OOM error came in at: [April/9/2018 0:56:55:806 am],
3. At [April/9/18 0:56:56:021 am] noticed TCP Channel TCP_1 has stopped listening on host * (IPv6) port 9061
4. At [April/9/18 0:56:56:790 am] application stopped
...
...
5. [April/9/18 0:57:59:879 am] 00000000 ManagerAdmin I TRAS0017I: The startup trace state is *=info:org.apache.struts.tiles.commands.TilesPreProcessor=off.

JVM starting...
Back to top
View user's profile Send private message
Display posts from previous:
Post new topicReply to topic Page 1 of 1

MQSeries.net Forum IndexWebSphere Application ServerDoes Garbage Collection (GC) trigger JVM restart?
Jump to:



You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
Protected by Anti-Spam ACP


Theme by Dustin Baccetti
Powered by phpBB 2001, 2002 phpBB Group

Copyright MQSeries.net. All rights reserved.