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CFLOCK issues in ColdFusion 8
Author: Hemant Khandelwal
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305549
Hi Wim,
Can you please mail me (hkhandel atadobedotcom) the java stacktrace and any repro
code from CF server that will help me in trying to debug this issue and fix it?
Thanks,
Hemant
Author: Brian Kotek
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305410
Ah OK, if this is just a simple named lock then that is definitely a common
thing. It sounded like you had a large number of locks that might be nested,
etc., which might be an indicator that some other approach could be
considered. Regardless, it's true that the memory tracking should not be
locking (ha ha) things up like this. I wasn't making excuses for the Server
Monitor, but rather just trying to see if there was an underlying issue that
might need attention regardless of this apparent bug in the Monitor.
Regards,
Brian
----- Excess quoted text cut - see Original Post for more -----
Author: Wim Lemmens
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305409
@Brian
It's clear that the locking is not the issue here, so I don't think there's much
reason to elaborate on that.
The problem is that a running process is blocked at a random point inside a lock
(when the Memory Tracking is activated). This causes the lock to be active for
ever (beyond the lock timeout), which prevents other requests from obtaining the
lock.
We are using named locks, so it doesn't really block the application, but just
that particular process. However, this behavior is seen in all processes (for
various named locks), so in practice, the whole application is blocked.
Stopping the Memory Tracking solves the issue.
Author: Brian Kotek
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305408
It may be a reason to re-examine what you're doing with so much locking
going on in the first place. You didn't mention the reason for your use of
so many CFLOCKS (which must be nested I assume based on what you're saying?)
but as Dave alluded, there may be other ways to deal with whatever the
underlying forces are.
----- Excess quoted text cut - see Original Post for more -----
Author: Wim Lemmens
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305399
@Tom
I agree and we didn't activate this on production, but I don't think it's normal
that this feature (which is built to help you solve issues) will cause this kind
of issues in the first place. I can live with some performance decrease, but
blocking the entire application makes this a "feature from hell" which should
never be used, not even on a development or test system.
Author: Tom Chiverton
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305396
> The problem was caused (believe it or not) by the ColdFusion monitor in
> CF8, and more specifically the Memory Tracking.
This is not recommended to be on in production. Only the first one of the
three is as the others have various levels of performance impact.
You wouldn't leave debugging on on a production box either, for the same
reason.
--
Tom Chiverton
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Author: Wim Lemmens
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305392
>Just a quick note, this bug is fixed in CF 8.0.1.
Just a quick note, I AM running CF 8.0.1
Back to the drawing board ;o)
Author: Hemant Khandelwal
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305391
Just a quick note, this bug is fixed in CF 8.0.1.
Author: Hemant Khandelwal
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305324
Hi Wim,
I think there is a hotfix for the same issue that we have built. I will check on
the same.
Thanks,
Hemant
Adobe ColdFusion Team
Author: Wim Lemmens
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305307
Thank you all for your replies.
The problem was caused (believe it or not) by the ColdFusion monitor in CF8, and
more specifically the Memory Tracking.
When I stopped the memory tracking, the issue does not occur anymore. I stopped
it yesterday and the application is now running fine for over 24 hours.
Whenever I activate the memory tracking again, we are having lock issues withing
3 minutes. When I stop it again, the problem goes away (after I kill the stuck
threads).
It seems that Adobe needs to look into the impact of the memory tracking some
more. They mention that it will have a negative impact on the performance (which
is totally understandable), but blocking an entire application from running is
just plain ridiculous.
Regards,
Wim.
Author: Hemant Khandelwal
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305219
Though it is not directly related to the problem mentioned here, there is an
interesting post by Simon on cflock http://www.horwith.com/index.cfm/2008/4/28/cflock-explained
Author: Dave Watts
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305180
> Because of the nature of our application and the way it is
> build, we use cflockextensively.
Why, exactly? In my experience, many applications overuse locks for various
reasons, such as requirements imposed by CF5 and earlier versions. There
shouldn't be that many things you need to lock from within CF (as opposed to
your database, which will be where most of your concurrency issues occur and
which you should solve by using whatever concurrency control your database
provides).
> We are using nested locks, but there are no deadlocks ...
I've seen various problems with nested locks before. I strongly recommend
that you replace them with a named lock scheme, or remove them entirely if
you can.
Dave Watts, CTO, Fig Leaf Software
http://www.figleaf.com/
Fig Leaf Training: Adobe/Google/Paperthin Certified Partners
http://training.figleaf.com/
WebManiacs 2008: the ultimate conference for CF/Flex/AIR developers!
http://www.webmaniacsconference.com/
Author: Hemant Khandelwal
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305179
Is it possible for you to take the thread dump and post it here?
Author: Wim Lemmens
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305152
Hi all,
We recently upgraded our test server from CFMX 6.1 to ColdFusion 8, which causes
our application much problems.
Because of the nature of our application and the way it is build, we use
cflockextensively.
It seems that ColdFusion 8 has some serious issues with CFLOCK. After the
upgrade, we found requests to be blocked for no obvious reason, while the CF
monitor always shows that the process is waiting for a lock (cflock is the final
element in the stack trace).
We are using nested locks, but there are no deadlocks (believe me, I checked).
Anyways, the CF documentation says that a deadlock would end when a timeout is
reached. I'm now looking at a request that has been blocked for over 3 days (lock
timeout = 30 seconds).
Here's the stack trace of the request:
**************************************
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/components/SharedDirectoryListing.cfc
cflock
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/components/SharedDirectoryListing.cfc
getNextItem() : 138
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/components/SharedDirectoryListing.cfc
check() : 116
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/tasks/archiving/setExpirydates.cfm
cflock : 51
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/tasks/archiving/setExpirydates.cfm
: 3
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/tasks/archiving/setExpirydates.cfm
**************************************
This is the only active request. No other requests are running. When I start a
new request that waits for the same lock, it waits for the lock for 30 seconds
and then times out, which leads me to believe that the long running request has
obtained the lock.
This code worked without any issues on CFMX6, so there has to be something
different in the way CF8 handles the locks.
Is there anybody out there that had similar issues after upgrading to CF8?
Is there a way to see all active locks on an application? The CF monitor does not
seem to be able to give me the information I need to solve this issue.
Any help would be much appreciated!
Thank you,
Wim
Belgium
Author: Wim Lemmens
Short Link: http://www.houseoffusion.com/groups/cf-talk/thread.cfm/threadid:56361#305151
Hi all,
We recently upgraded our test server from CFMX 6.1 to ColdFusion 8, which causes
our application much problems.
Because of the nature of our application and the way it is build, we use
cflockextensively.
It seems that ColdFusion 8 has some serious issues with CFLOCK. After the
upgrade, we found requests to be blocked for no obvious reason, while the CF
monitor always shows that the process is waiting for a lock (cflock is the final
element in the stack trace).
We are using nested locks, but there are no deadlocks (believe me, I checked).
Anyways, the CF documentation says that a deadlock would end when a timeout is
reached. I'm now looking at a request that has been blocked for over 3 days (lock
timeout = 30 seconds).
Here's the stack trace of the request:
**************************************
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/components/SharedDirectoryListing.cfc
cflock
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/components/SharedDirectoryListing.cfc
getNextItem() : 138
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/components/SharedDirectoryListing.cfc
check() : 116
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/tasks/archiving/setExpirydates.cfm
cflock : 51
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/tasks/archiving/setExpirydates.cfm
: 3
at
/opt/bea/wls_sp6/user_projects/domains/domaineistc/extend7010/stage/cfusion-ear/cfusion-war/eistc/tasks/archiving/setExpirydates.cfm
**************************************
This is the only active request. No other requests are running. When I start a
new request that waits for the same lock, it waits for the lock for 30 seconds
and then times out, which leads me to believe that the long running request has
obtained the lock.
This code worked without any issues on CFMX6, so there has to be something
different in the way CF8 handles the locks.
Is there anybody out there that had similar issues after upgrading to CF8?
Is there a way to see all active locks on an application? The CF monitor does not
seem to be able to give me the information I need to solve this issue.
Any help would be much appreciated!
Thank you,
Wim
Belgium
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May 24, 2012
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