From: "Hugi Thordarson" <webobjects-dev@wocommunity.org>
Received-SPF: none
 receiver=post.selbstdenker.com; client-ip=93.95.224.70; envelope-from=hugi@karlmenn.is
Content-Type: text/plain;
	charset=utf-8
Content-Transfer-Encoding: quoted-printable
Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.4\))
Subject: Re: [WO-DEV] Urgent Out of Memory help needed
Date: Mon, 8 Feb 2021 09:18:16 +0000
References: <list-25375317@post.selbstdenker.com>
To: WebObjects & WOnder Development <webobjects-dev@wocommunity.org>
In-Reply-To: <list-25375317@post.selbstdenker.com>
Message-Id: <9D5C60C7-3A4A-4306-A7E9-C161800F399B@karlmenn.is>

Hi Markus!

to start somewhere, you could set the VM properties =
-XX:+HeapDumpOnOutOfMemoryError and =
-XX:HeapDumpPath=3D/tmp/or/some/other/dir on your app.
When the app crashes, you'll get a heap dump that can be analyzed to =
look for classes with a suspicious amount of allocations, using a tool =
such as VisualVM.

I consider the instance stats in JavaMonitor pure fiction, my apps =
usually show tens of thousands of active sessions there which is=E2=80=A6 =
not correct. I usually enable WOStats on an app by setting a password =
for the stats store in my Application constructor =
(statisticsStore().setPassword( "smu" ) ). The URL is then =
[appURL]/wa/WOStats, leave the username empty and just enter the =
password.

- hugi


> On 8 Feb 2021, at 08:42, Markus Ruggiero (rucotec) =
<webobjects-dev@wocommunity.org> wrote:
>=20
> We are running the same application code in a handful of instances. =
Each instance is dedicated to one customer. There are only some very =
small differences between the instances like db credentials and some =
webserver resources (customer specific logo etc). One customer is =
driving their dedicated instance regularly into java memory exhaustion, =
all others have no problem. This particular customer is using one screen =
more than other customers do. This screen has a couple Ajax components, =
but as far as I can tell nothing too fancy. In WOMonitor we can see that =
the Running Session count at the bottom right of the details display =
goes up like crazy. Within hours the count can reach 1500+. I started to =
trace all Session creation (Thread.dumpStack() in Session constructor) =
but as expected there was exactly one session being created at login, =
then none more.=20
>=20
> What the heck is going on here? What does WOMonitor display here? =
Obviously must be something other than just session creation. Could this =
be an Ajax issue? Where would you start? We upped the JVM memory to 2G =
to survive the day and have more instances for that particular customer =
running.
>=20
> Btw: how do you go into WOStatistics? Setting a statistics password in =
WOMonitor did not help, the direct action always comes back with a =
browser error (Safari can=E2=80=99t open the page bla bla bla). I seem =
the miss something here.
>=20
> Thanks for any help
> ---markus---
>=20
> Markus Ruggiero
>=20
> rucotec GmbH                        web https://rucotec.ch
> Steinenvorstadt 79                email markus.ruggiero@rucotec.ch
> 4051 Basel / Switzerland         mobile +41 79 508 4701
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20