As far as I understand Alexei, the issue here is that Ignite kernal
doesn't have list of all the threads that accessed it during its lifetime.
So the kernal won't be able to iterate over all the threads (like
threads from Tomcat thread pool) and perform all the cleaning. This is
the issue.
--
Denis
On 4/6/2016 11:47 AM, Artem Shutak wrote:
Alexei,
I would follow the Valentin's suggestion in the issue description and would
add to Ignite tests a check on thread locals after stopping all grids. And
then we will be able to fix thread local cleaning in all places.
Thanks,
-- Artem --
On Wed, Apr 6, 2016 at 11:18 AM, Alexei Scherbakov <
alexey.scherbak...@gmail.com> wrote:
Valentin,
I did test on demo web app where HttpSession is backed by Ignite cache and
collect some logs.
There are many places in Ignite where thread locals are used.
Then cache methods are accessed in threads from servlet container pool, we
get leaks.
I don't think it will be easy to add thread locals cleaning in all these
places without major code rewrite, but, for sure, it would be ideal
solution.
<E0><EF><F0> 05, 2016 4:21:52 PM
org.apache.catalina.loader.WebappClassLoaderBase
checkThreadLocalMapForLeaks
SEVERE: The web application [/app1] created a ThreadLocal with key of type
[org.apache.ignite.internal.util.GridSpinReadWriteLock$1] (value
[org.apache.ignite.internal.util.GridSpinReadWriteLock$1@5fecc35f]) and a
value of type [java.lang.Integer] (value [0]) but failed to remove it when
the web application was stopped. Threads are going to be renewed over time
to try and avoid a probable memory leak.
<E0><EF><F0> 05, 2016 4:21:52 PM
org.apache.catalina.loader.WebappClassLoaderBase
checkThreadLocalMapForLeaks
SEVERE: The web application [/app1] created a ThreadLocal with key of type
[org.apache.ignite.internal.util.tostring.GridToStringBuilder$1] (value
[org.apache.ignite.internal.util.tostring.GridToStringBuilder$1@4ecdfc04])
and a value of type [java.util.LinkedList] (value
[[org.apache.ignite.internal.util.tostring.GridToStringThreadLocal@684a2791
]])
but failed to remove it when the web application was stopped. Threads are
going to be renewed over time to try and avoid a probable memory leak.
<E0><EF><F0> 05, 2016 4:21:52 PM
org.apache.catalina.loader.WebappClassLoaderBase
checkThreadLocalMapForLeaks
SEVERE: The web application [/app1] created a ThreadLocal with key of type
[org.apache.ignite.internal.binary.BinaryThreadLocalContext$1] (value
[org.apache.ignite.internal.binary.BinaryThreadLocalContext$1@4e9300e7])
and a value of type
[org.apache.ignite.internal.binary.BinaryThreadLocalContext] (value
[org.apache.ignite.internal.binary.BinaryThreadLocalContext@7934a88]) but
failed to remove it when the web application was stopped. Threads are going
to be renewed over time to try and avoid a probable memory leak.
<E0><EF><F0> 05, 2016 4:21:52 PM
org.apache.catalina.loader.WebappClassLoaderBase
checkThreadLocalMapForLeaks
SEVERE: The web application [/app1] created a ThreadLocal with key of type
[java.lang.ThreadLocal] (value [java.lang.ThreadLocal@56502b72]) and a
value of type
[org.apache.ignite.internal.binary.streams.BinaryMemoryAllocatorChunk]
(value
[org.apache.ignite.internal.binary.streams.BinaryMemoryAllocatorChunk@4eab9d2f
])
but failed to remove it when the web application was stopped. Threads are
going to be renewed over time to try and avoid a probable memory leak.
<E0><EF><F0> 05, 2016 4:21:52 PM
org.apache.catalina.loader.WebappClassLoaderBase
checkThreadLocalMapForLeaks
SEVERE: The web application [/app1] created a ThreadLocal with key of type
[java.lang.ThreadLocal] (value [java.lang.ThreadLocal@eb53c9d]) and a
value
of type
[org.apache.ignite.marshaller.optimized.OptimizedObjectStreamRegistry.StreamHolder]
(value
[org.apache.ignite.marshaller.optimized.OptimizedObjectStreamRegistry$StreamHolder@5e2c15f7
])
but failed to remove it when the web application was stopped. Threads are
going to be renewed over time to try and avoid a probable memory leak.
<E0><EF><F0> 05, 2016 4:21:52 PM
org.apache.catalina.loader.WebappClassLoaderBase
checkThreadLocalMapForLeaks
SEVERE: The web application [/app1] created a ThreadLocal with key of type
[org.apache.ignite.internal.util.GridSpinReadWriteLock$1] (value
[org.apache.ignite.internal.util.GridSpinReadWriteLock$1@55b9da28]) and a
value of type [java.lang.Integer] (value [0]) but failed to remove it when
the web application was stopped. Threads are going to be renewed over time
to try and avoid a probable memory leak.
<E0><EF><F0> 05, 2016 4:21:52 PM
org.apache.catalina.loader.WebappClassLoaderBase
checkThreadLocalMapForLeaks
SEVERE: The web application [/app1] created a ThreadLocal with key of type
[org.apache.ignite.internal.util.StripedCompositeReadWriteLock$1] (value
[org.apache.ignite.internal.util.StripedCompositeReadWriteLock$1@1ac73431
])
and a value of type [java.lang.Integer] (value [9]) but failed to remove it
when the web application was stopped. Threads are going to be renewed over
time to try and avoid a probable memory leak.
SEVERE: The web application [/app1] created a ThreadLocal with key of type
[org.apache.ignite.internal.processors.cache.GridCacheAdapter$5] (value
[org.apache.ignite.internal.processors.cache.GridCacheAdapter$5@28a1bd99])
and a value of type
[org.apache.ignite.internal.processors.cache.GridCacheAdapter.FutureHolder]
(value
[org.apache.ignite.internal.processors.cache.GridCacheAdapter$FutureHolder@6763d70c
])
but failed to remove it when the web application was stopped. Threads are
going to be renewed over time to try and avoid a probable memory leak.
As a solution, I propose to implement servlet filter as a part of Ignite
web integration, which will be responsible for cleaning up all thread
locals after request processing.
Filter must be executed last in filter chain to work correctly.
It is not necessary to use the filter in case of Tomcat, because it
provides own solution to the problem requiring special configuration
parameter for context
User should decide which approach is better to him.
2016-04-06 1:45 GMT+03:00 Valentin Kulichenko <
valentin.kuliche...@gmail.com
:
Alexei,
I would start with defining which thread locals cause this and why they
are
not properly cleaned on node shutdown. Ideally, this should never happen.
-Val
On Tue, Apr 5, 2016 at 10:36 AM, Alexei Scherbakov <
alexey.scherbak...@gmail.com> wrote:
Hello.
Currently I'm working on the IGNITE-967
<https://issues.apache.org/jira/browse/IGNITE-967>.
In fact, it is well known, easily reproduceable, ClassLoader memory
leak
problem in managed environments, such as servlet containers.
See http://wiki.apache.org/tomcat/MemoryLeakProtection to read more on
that.
In short, the code using thread locals is responsible for cleaning them
after request processing
to prevent memory leaks related to different lifetime of application
and
thread in pool.
Also blindly reusing thread from pool can be dangerous, because current
ThreadLocal value can be different from expected default value.
One posiible way of solving the problem is using post-processing
Filter,
which is responsible for cleaning all thread locals on current thread.
Another approach would be sticking with container's specific solution
to
this problem.
On example, tomcat provides the configuration property
renewThreadsWhenStoppingContext,
which forces it to renew threads involved in servicing requests for
destroyed context, thus removing leaks.
What do you think?
--
Best regards,
Alexei Scherbakov
--
Best regards,
Alexei Scherbakov
