Re: Deadlocks
Re: Deadlocks
- Subject: Re: Deadlocks
- From: Simon McLean <email@hidden>
- Date: Mon, 10 Sep 2007 18:18:21 +0100
Hi Guido -
Many thanks for that URL - and thanks to everyone else that posted
ideas. We had to let the app fall over quite a few times and grab a
half dozen stack traces before we figured it out, but the app is
humming along nicely once again now.
We ended up finding 2 core issues:
1) the occasional use of new EOEditingContext() instead of
ERXEC.newEditingContext()
2) use of the session's editing context inside a thread
Both were well buried sins that once the app scaled up became rather
ugly :-(
Thanks again,
Simon
On 5 Sep 2007, at 23:14, Guido Neitzer wrote:
On 05.09.2007, at 16:01, Simon McLean wrote:
We're experiencing some pretty bad deadlock issues at the moment
and I'm pretty convinced it's down to EC lock abuse.
Get a stacktrace of your running application to verify that:
http://tinyurl.com/3bpkkv
... we should never have to manually lock or unlock an EC ?
That is true, yes - but you still might run into problems if you do
bad things.
Or put another way, when using these rules is there any situation
that we would have to call ec.lock() or ec.unlock() in our code ?
I normally lock and unlock manually on long response pages / tasks,
as the unlocking of editing contexts relies on the request response
loop.
If you see problems in the stacktrace, when the session gets
checked out from the session store, make sure you NEVER EVER touch
something from the session's default editing context inside your
"performAction" method on a long response page. This will autolock
your session's default editing context, it will not get unlocked,
because you are outside of the rr loop and the next checkout for
that session will fail.
The other thing I saw with deadlocks: if you run out of space on
your server, log4j might deadlock.
cug
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| References: | |
| | >Deadlocks (From: Simon McLean <email@hidden>) |
| | >Re: Deadlocks (From: Guido Neitzer <email@hidden>) |