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Posted to users@tomcat.apache.org by Darren Kukulka <Da...@connaught.plc.uk> on 2006/09/15 16:59:20 UTC
Perm Gen not being released in GC
Hi All,
Throughput Garbage collection on a 5.5.15 Tomcat instance is failing to
release Old Gen heap space when it becomes full on one of our Windows
installations.
For the most part GC does release memory - in a typical working day this is
an upward trend in terms of the amount of heap reclaimed, gradually becoming
a downward trend late in the day.
Every now and then JConsole shows Old Gen as having flat-lined. Only a
Tomcat restart can rectify the problem. Killing sessions followed by a
manual GC does not seem to have an effect.
Haven't yet determined whether we need to start looking at the young to old
heap allocation ratios - is this the main area I should be looking into?
Any thoughts would be appreciated.
Cheers,
Darren Kukulka
Connaught honoured AIM 'Decade of Excellence' Award
Connaught awarded Partnering Contractor of the Year 2005
Connaught wins AIM 'Company of the Year' award 2004
West of England Business of the Year Award Winner 2003
Why not visit our website http://www.connaught.plc.uk
Disclaimer:
The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete this message.
Connaught plc, Head Office 01392 444546
Re: Perm Gen not being released in GC
Posted by Nikola Milutinovic <al...@yahoo.com>.
> Im a Project Manager, not a techie but we had the same problem and had to
> increase the perm gen to the following: Tomcat sets it at default at 64MB.
> Perm Gen Memory: 150 MB
> Max Perm Gen: 256 MB
Perm gen is memory reserved for class loading and is directly proportional to the number/size of classes you load.
> We where getting perm gen out of memory errors which is why we did this.
> This stabilised the environment but we still have problems with our Heap
> Memory filling up and not been garbage collected properly.
That sounds like a memory leak.
Nix.
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Re: Perm Gen not being released in GC
Posted by ad...@nl.abnamro.com.
Hi Stephanie,
Im a Project Manager, not a techie but we had the same problem and had to
increase the perm gen to the following: Tomcat sets it at default at 64MB.
Perm Gen Memory: 150 MB
Max Perm Gen: 256 MB
We where getting perm gen out of memory errors which is why we did this.
This stabilised the environment but we still have problems with our Heap
Memory filling up and not been garbage collected properly.
Kind Regards
Adrena Keating
EDS Project Manager,
ABN AMRO NL Solution Centre
Tel: +31-20-6299038
Mobile: +31-6-22574953
Stephen Caine
<stephen@commong To: "Tomcat Users List" <us...@tomcat.apache.org>
rnd.com> cc:
Subject: Re: Perm Gen not being released in GC
09/15/2006 05:31
PM
Please respond
to "Tomcat Users
List"
Darren,
> Every now and then JConsole shows Old Gen as having flat-lined.
> Only a Tomcat restart can rectify the problem. Killing sessions
> followed by a manual GC does not seem to have an effect.
>
> Haven't yet determined whether we need to start looking at the
> young to old heap allocation ratios - is this the main area I
> should be looking into?
We see this same behavior. I too am interested in comments from
others. We are running on a OS X Server; JVM v1.5.
Stephen Caine
Soft Breeze Systems, LLC
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Re: Perm Gen not being released in GC
Posted by Stephen Caine <st...@commongrnd.com>.
Darren,
> Every now and then JConsole shows Old Gen as having flat-lined.
> Only a Tomcat restart can rectify the problem. Killing sessions
> followed by a manual GC does not seem to have an effect.
>
> Haven't yet determined whether we need to start looking at the
> young to old heap allocation ratios - is this the main area I
> should be looking into?
We see this same behavior. I too am interested in comments from
others. We are running on a OS X Server; JVM v1.5.
Stephen Caine
Soft Breeze Systems, LLC
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Re: Perm Gen not being released in GC
Posted by "david.delbecq" <da...@oma.be>.
This has been discussed quite a lot on mailing list. Lots of things can
generate memory leaks in webapp environment. Amongst others:
- not nullifying threadlocal variable.
- use of singleton pattern
- some bugged versions of CGlib
take a look at older messages in this mailing list
http://marc.theaimsgroup.com/?l=tomcat-user&w=2&r=1&s=permgen&q=b
Darren Kukulka a écrit :
> Hi All,
>
>
>
> Throughput Garbage collection on a 5.5.15 Tomcat instance is failing to
> release Old Gen heap space when it becomes full on one of our Windows
> installations.
>
>
>
> For the most part GC does release memory - in a typical working day this is
> an upward trend in terms of the amount of heap reclaimed, gradually becoming
> a downward trend late in the day.
>
>
>
> Every now and then JConsole shows Old Gen as having flat-lined. Only a
> Tomcat restart can rectify the problem. Killing sessions followed by a
> manual GC does not seem to have an effect.
>
>
>
> Haven't yet determined whether we need to start looking at the young to old
> heap allocation ratios - is this the main area I should be looking into?
>
>
>
> Any thoughts would be appreciated.
>
>
>
> Cheers,
>
> Darren Kukulka
>
>
>
>
>
> Connaught honoured AIM 'Decade of Excellence' Award
>
>
>
> Connaught awarded Partnering Contractor of the Year 2005
>
>
>
> Connaught wins AIM 'Company of the Year' award 2004
>
>
>
> West of England Business of the Year Award Winner 2003
>
>
>
> Why not visit our website http://www.connaught.plc.uk
>
>
>
> Disclaimer:
>
> The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete this message.
>
>
>
> Connaught plc, Head Office 01392 444546
>
>
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RE: Perm Gen not being released in GC
Posted by Tracy Nelson <tn...@factsmgt.com>.
Are you sure you don't have a memory leak?
FWIW, I had a client with a situation like this, we wound up throwing in
a stopgap that consisted of a thread that checked free space once a
minute and explicitly invoked System.gc() if certain parameters were
met. Not the solution I originally proposed, but it was something I
could do in one day (the length of my contract) and it was cheaper than
buying a heap analyzer (a la JProbe).
---
Tracy Nelson / Nelnet Business Solutions
402 / 617-9449
| -----Original Message-----
| From: Darren Kukulka [mailto:Darren.Kukulka@connaught.plc.uk]
| Sent: Friday, 15 September, 2006 09:59
| To: Tomcat Users List
| Subject: Perm Gen not being released in GC
|
| Hi All,
|
|
|
| Throughput Garbage collection on a 5.5.15 Tomcat instance is failing
to
| release Old Gen heap space when it becomes full on one of our Windows
| installations.
|
|
|
| For the most part GC does release memory - in a typical working day
this
| is
| an upward trend in terms of the amount of heap reclaimed, gradually
| becoming
| a downward trend late in the day.
|
|
|
| Every now and then JConsole shows Old Gen as having flat-lined. Only
a
| Tomcat restart can rectify the problem. Killing sessions followed by
a
| manual GC does not seem to have an effect.
|
|
|
| Haven't yet determined whether we need to start looking at the young
to
| old
| heap allocation ratios - is this the main area I should be looking
into?
|
|
|
| Any thoughts would be appreciated.
|
|
|
| Cheers,
|
| Darren Kukulka
|
|
|
|
|
| Connaught honoured AIM 'Decade of Excellence' Award
|
|
|
| Connaught awarded Partnering Contractor of the Year 2005
|
|
|
| Connaught wins AIM 'Company of the Year' award 2004
|
|
|
| West of England Business of the Year Award Winner 2003
|
|
|
| Why not visit our website http://www.connaught.plc.uk
|
|
|
| Disclaimer:
|
| The information transmitted is intended only for the person or entity
to
| which it is addressed and may contain confidential and/or privileged
| material. Any review, retransmission, dissemination or other use of,
or
| taking of any action in reliance upon, this information by persons or
| entities other than the intended recipient is prohibited. If you
received
| this in error, please contact the sender and delete this message.
|
|
|
| Connaught plc, Head Office 01392 444546
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