Howdy,
Enable verbose GC (see Java VM Options for how to do this).
Yoav Shapira
Millennium ChemInformatics
-Original Message-
From: Christian Witucki [mailto:[EMAIL PROTECTED]
Sent: Wednesday, January 14, 2004 9:00 AM
To: [EMAIL PROTECTED]
Subject: Memory Leaks
Does anyone know that
I've been looking at this this week and have resolved that we need to buy a JVM
Profiler, prob. JProfiler.
-Original Message-
From: Christian Witucki [mailto:[EMAIL PROTECTED]
Sent: 14 January 2004 14:00
To: [EMAIL PROTECTED]
Subject: Memory Leaks
Does anyone know that when Garbage
I have a problem with memory leak.
You have see my message BIG PROBLEM // LINUX TOMCAT SSL ?
-Message d'origine-
De : Christian Witucki [mailto:[EMAIL PROTECTED]
Envoy : mercredi 14 janvier 2004 15:00
: [EMAIL PROTECTED]
Objet : Memory Leaks
Does anyone know that when Garbage
My understanding is that the GC runs on a low-priority
thread, so you never get to tell it when to run. The
operating system and JVM deal with it.
I also recall reading that memory is returned to the
JVM, but not released back to the OS. So if you're
watching Memory Usage in the Windows Task
: Michael Duffy [mailto:[EMAIL PROTECTED]
Sent: 14 January 2004 14:07
To: Tomcat Users List
Subject: Re: Memory Leaks
My understanding is that the GC runs on a low-priority
thread, so you never get to tell it when to run. The
operating system and JVM deal with it.
I also recall reading
at www.java.sun.com
Hope this helps
Pete
-Original Message-
From: Michael Duffy [mailto:[EMAIL PROTECTED]
Sent: 14 January 2004 14:07
To: Tomcat Users List
Subject: Re: Memory Leaks
My understanding is that the GC runs on a low-priority
thread, so you never get to tell it when to run
Hi!
Shapira, Yoav wrote:
This is a common misconception: System.gc() is merely a suggestion to
the VM to run collection. The VM is not obliged to run it then, i.e.
this is not a hard directive. It should never be relied upon. With JDK
1.4, there's a runtime parameter to ignore System.gc()
()) This indicated, that
(with that specific vm) the call to gc() did
something.
-Original Message-
From: Shapira, Yoav [mailto:[EMAIL PROTECTED]
Sent: Wednesday, January 14, 2004 3:43 PM
To: Tomcat Users List
Subject: RE: Memory Leaks
This is a common misconception: System.gc
Yoav,
With JDK
1.4, there's a runtime parameter to ignore System.gc() calls and that
parameter may be on by default in the future.
What is this parameter? I've never seen it before...
-chris
-
To unsubscribe, e-mail: [EMAIL
Howdy,
With JDK
1.4, there's a runtime parameter to ignore System.gc() calls and that
parameter may be on by default in the future.
What is this parameter? I've never seen it before...
-chris
-XX:+DisableExplicitGC is the parameter, which I believe has been
available since JDK 1.4.0.
Yoav,
With JDK
1.4, there's a runtime parameter to ignore System.gc() calls and that
parameter may be on by default in the future.
What is this parameter? I've never seen it before...
-XX:+DisableExplicitGC is the parameter, which I believe has been
available since JDK 1.4.0.
Wow, I didn't know
http://java.sun.com/docs/hotspot/VMOptions.html
-Original Message-
From: Christopher Schultz [mailto:[EMAIL PROTECTED]
Sent: Wednesday, January 14, 2004 4:17 PM
To: Tomcat Users List
Subject: Re: Memory Leaks
Wow, I didn't know that -XX parameters existed. Where can I get more
Users List [EMAIL PROTECTED]
cc:
Vedr.: Re: Memory Leaks
Yoav,
With JDK
1.4, there's a runtime parameter to ignore System.gc() calls and that
parameter may be on by default in the future.
What is this parameter? I've never seen it before...
-XX:+DisableExplicitGC
Thomas,
sorry for interrupting but if you into optimizing your JVM setting as well
as explorings its options I would recommend:
Perhaps some of the more savvy developers can give more directions.
Thanks for the pointers. Actually, I'm not having any performance
problems at the moment :)
As
: Tomcat Users List
Objet : Re: RE : memory-leaks in servlets, tool for tracing ?
Laurent,
What about classes with static method and/or static attributes ?
Are they deleted from the old webapp ?
I don't believe that the VM ever releases resources taken up by Class
objects (I think this includes
Howdy,
context-reload occurs. The solution, of course, is not to enable
context-reloading on production :)
This is very good advice.
Yoav Shapira
This e-mail, including any attachments, is a confidential business communication, and
may contain information that is confidential, proprietary
Laurent,
When does a class reload occur ?
I was talking about a context re-load, which dumps everything in the
context and re-starts it in a new ClassLoader.
When u update a JSP ?
Yes, the class gets re-loaded, but not the whole context. This is much
less of a problem.
When u update a class ?
Christopher,
thanks for your comprehensive response !
See more comments down ...
- Original Message -
From: Christopher Schultz [EMAIL PROTECTED]
To: Tomcat Users List [EMAIL PROTECTED]
Sent: Wednesday, October 29, 2003 3:29 PM
Subject: Re: memory-leaks in servlets, tool for tracing
Grisi,
our TC-based webapplication performs well but the java-processes
concerned are showing increasing memory usage over time. For tracing
we already stripped the app down to the very basic to get a clue.
Wasn't successful enough.
Have you looked at the memory over a long time, including
Howdy,
our TC-based webapplication performs well but the java-processes
concerned are showing increasing memory usage over time. For tracing
This basic idea that memory usage should be constant over time is very
common and usually wrong. The JVM will use as much memory as it needs
without
Yoav,
You make a great point about how the app should stabilize it's memory
usage over time. However, I've got a question about memory usage when I
stop (via Tomcat manager) and reload a webapp via a WAR file. If I
understand your point, and I'm close to the max heap size, shouldn't GC
free
Howdy,
You make a great point about how the app should stabilize it's memory
usage over time. However, I've got a question about memory usage when I
stop (via Tomcat manager) and reload a webapp via a WAR file. If I
understand your point, and I'm close to the max heap size, shouldn't GC
free up
What about classes with static method and/or static attributes ?
Are they deleted from the old webapp ?
-Message d'origine-
De : Shapira, Yoav [mailto:[EMAIL PROTECTED]
Envoyé : mercredi 5 novembre 2003 15:57
À : Tomcat Users List
Objet : RE: memory-leaks in servlets, tool for tracing
Objet : RE : memory-leaks in servlets, tool for tracing ?
What about classes with static method and/or static attributes ?
Are they deleted from the old webapp ?
-Message d'origine-
De : Shapira, Yoav [mailto:[EMAIL PROTECTED]
Envoyé : mercredi 5 novembre 2003 15:57
À : Tomcat Users List
-Original Message-
From: Laurent Michenaud [mailto:[EMAIL PROTECTED]
Sent: Wednesday, November 05, 2003 10:59 AM
To: Tomcat Users List
Subject: RE : RE : memory-leaks in servlets, tool for tracing ?
It would be good if some of you writes an kind of howTo
that shows :
- a webapp with a memory
Laurent,
What about classes with static method and/or static attributes ?
Are they deleted from the old webapp ?
I don't believe that the VM ever releases resources taken up by Class
objects (I think this includes static resources for a class). There used
to be a VM option, -noclassgc, that was
Howdy,
I like OptimizeIt's heap snapshots.
Yoav Shapira
Millennium ChemInformatics
-Original Message-
From: Dirk Griesbach [mailto:[EMAIL PROTECTED]
Sent: Wednesday, October 29, 2003 4:03 AM
To: Tomcat Users List
Subject: memory-leaks in servlets, tool for tracing ?
hi everybody,
our
Grisi,
our TC-based webapplication performs well but the java-processes
concerned are showing increasing memory usage over time. For tracing
we already stripped the app down to the very basic to get a clue.
Wasn't successful enough.
Have you looked at the memory over a long time, including
?
-Original Message-
From: Jim Lynch [mailto:[EMAIL PROTECTED]
Sent: Friday, September 05, 2003 9:37 AM
To: Tomcat Users List
Subject: Re: Memory leaks?
I'm most certain the connections are closed but there may be
a few dangling statements. I'm using mysql jdbc
But depending on the DB, it can cause problems from the DB with too many
open ResultSets... I had an issue with performance testing where everything
but ResultSets were being closed and the Oracle DB started throwing errors
after about 500 queries. Better safe than sorry.
Well, from what I
The JDBC spec states that when a connection is closed, all dependent assets
should also be closed. So if you are using a pool, make sure your pool is
compliant since the connection is never closed until the pool closes it.
When garbage collection runs is a whole different story. But its just
Tim Funk wrote:
The JDBC spec states that when a connection is closed, all dependent
assets should also be closed. So if you are using a pool, make sure your
pool is compliant since the connection is never closed until the pool
closes it.
So, that means that if you have a pool of ten
It depends. If your webapp calls connection.close(), then the result sets
*should* be closed.
But that is based one of the following assumptions:
- Your connection is the actual db connection and the driver is JDBC compliant
- The connection is a facade to the actual connection for the sake of
It's simple good practice to close objects that have close methods when you
no longer need them (as you do with stream objects, for example).
The spec says that ResultSet objects are closed when their Statement objects
are closed and that Statement objects are closed when their Connection
objects
Millennium ChemInformatics
-Original Message-
From: Greg Ward [mailto:[EMAIL PROTECTED]
Sent: Thursday, September 04, 2003 10:05 AM
To: Tomcat Users List; [EMAIL PROTECTED]
Subject: Re: Memory leaks?
On 03 September 2003, Jim Lynch said:
OK, that's probably what's going on. I know I
?
-Original Message-
From: Jim Lynch [mailto:[EMAIL PROTECTED]
Sent: Friday, September 05, 2003 9:37 AM
To: Tomcat Users List
Subject: Re: Memory leaks?
I'm most certain the connections are closed but there may be
a few dangling statements. I'm using mysql jdbc. Not using
pools since I
?
-Original Message-
From: Jim Lynch [mailto:[EMAIL PROTECTED]
Sent: Friday, September 05, 2003 9:37 AM
To: Tomcat Users List
Subject: Re: Memory leaks?
I'm most certain the connections are closed but there may be
a few dangling statements. I'm using mysql jdbc. Not using
, they
are just freed at different times. If you get a out of memory
error, there rn't any object that can be freed.
-Original Message-
From: Richard Hill [mailto:[EMAIL PROTECTED]
Sent: Wednesday, September 03, 2003 7:40 PM
To: 'Tomcat Users List'
Subject: RE: Memory leaks?
Try
?
Thanks
Alain
-Message d'origine-
De : Paul [mailto:[EMAIL PROTECTED]
Envoyé : mercredi, 3. septembre 2003 21:28
À : Tomcat Users List
Objet : Re: Memory leaks?
Docs indicate that leaving a stmt or rs object open can cause memory leaks.
Found the following in the tomcat docs somewhere, i
: Thursday, September 04, 2003 2:00 AM
To: Tomcat Users List
Subject: RE: Memory leaks?
In my experience this is not a good recommendation:
- -server is less stable than -client in all JDK's that I tried,
and this has been confirmed by several list members.
- -server won't help much on out
On 03 September 2003, Jim Lynch said:
OK, that's probably what's going on. I know I should close Statements
and Connections and do normally but I'm fairly certain I've some out
there dangling. I didn't know you had to close ResultSets, however.
Glad to know that.
You don't have to close
-
From: Greg Ward [mailto:[EMAIL PROTECTED]
Sent: Thursday, September 04, 2003 10:05 AM
To: Tomcat Users List; [EMAIL PROTECTED]
Subject: Re: Memory leaks?
On 03 September 2003, Jim Lynch said:
OK, that's probably what's going on. I know I should close
Statements
and Connections and do normally
-
From: Greg Ward [mailto:[EMAIL PROTECTED]
Sent: Thursday, September 04, 2003 9:05 AM
To: Tomcat Users List; [EMAIL PROTECTED]
Subject: Re: Memory leaks?
On 03 September 2003, Jim Lynch said:
OK, that's probably what's going on. I know I should close Statements
and Connections and do
Try passing the jvm the -server option
-Original Message-
From: Jim Lynch [mailto:[EMAIL PROTECTED]
Sent: Wednesday, September 03, 2003 9:57 AM
To: tomcat
Subject: Memory leaks?
I seemed to have read that java/tomcat isn't supposed to have memory
leaks, but something seems to be running
Docs indicate that leaving a stmt or rs object open can cause memory leaks.
Found the following in the tomcat docs somewhere, i think:
Here is an example of properly written code to use a db connection obtained
from a connection pool:
Connection conn = null;
Statement stmt = null; // Or
OK, that's probably what's going on. I know I should close Statements
and Connections and do normally but I'm fairly certain I've some out
there dangling. I didn't know you had to close ResultSets, however.
Glad to know that.
Thanks,
Jim.
Paul wrote:
Docs indicate that leaving a stmt or rs
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