Re: Equivalent for PerSessionPageStore in Wicket 9

Sven Meier Sat, 11 Apr 2020 14:02:26 -0700

Hi Thomas,

actually not bad news at all (for Wicket 9 at least).

The old page manager implementation had so many special concepts andsolutions, it's easy to miss one.

A soft reference feature can easily be added/restored. I'm alreadychecking where it fits best.


Thanks for your thorough testing.

Best regards
Sven


On 11.04.20 10:58, Thomas Heigl wrote:

Hi all,

Bad news. My application was caught in a GC loop after running for 8 hours.
The old generation was exhausted.

I couldn't get a heap dump at that time but restarted the application, took
a heap dump after about an hour, and reverted back to Wicket 8.

The problem is this: The heap was full of objects referencing
InMemoryPageStore, i.e. the in-memory 2nd-level cache for pages. My first
thought was that there is something wrong with the implementation of that
store and pages do not get limited or removed correctly.  So I debugged
it locally but everything is working fine.

Then I noticed that there are a lot of instances of Hibernate entities on
the heap. So there definitely is an issue with models somewhere in my
application. To be sure that this is not a new issue, I took another heap
dump from production - now running Wicket 8 again - and compared it.
There are undetached entity models on the heap as well.

So why does it not OOM with Wicket 8? Well, the PerSessionPageStore
(roughly the equivalent of InMemoryPageStore in Wicket 9) uses
SoftReferences for storing pages. InMemoryPageStore does not and GC cannot
reclaim memory from it.

So while this surfaced some issues in my application that I just fixed, I
believe that InMemoryPageStore should use SoftReferences or another
implementation based on SoftReferences should be added to Wicket 9. A cache
should not consume all the memory if it can easily re-fetch
the value from persistent storage.

I guess the reason for not using SoftReferences in InMemoryPageStore is
that it can theoretically be used as a "persistent" store for pages. If that
behavior is really required, I suggest adding another implementation using
SoftReferences.

Best regards,

Thomas

On Fri, Apr 10, 2020 at 7:19 PM Martin Grigorov <mgrigo...@apache.org>
wrote:

On Fri, Apr 10, 2020 at 4:01 PM Thomas Heigl <tho...@umschalt.com> wrote:

FYI: I deployed Wicket 9.0.0-M5 to production an hour ago. 100k requests
served and no issues so far.

Awesome!
Thank you for testing it!

Great work!

Thomas

On Wed, Apr 8, 2020 at 3:13 PM Sven Meier <s...@meiers.net> wrote:

Many thanks Maxim!

Sven

On 08.04.20 14:29, Maxim Solodovnik wrote:

Released :)

On Wed, 8 Apr 2020 at 15:41, Maxim Solodovnik <solomax...@gmail.com>

wrote:

OK

Will start new release process in couple of hours
Please stop me if you will find any blocker :)

On Wed, 8 Apr 2020 at 14:36, Thomas Heigl <tho...@umschalt.com>

wrote:

Hi Maxim,

It works for me now!

Thomas

On Wed, Apr 8, 2020 at 9:17 AM Maxim Solodovnik <

solomax...@gmail.com>

wrote:

Thanks a million!

On Wed, 8 Apr 2020 at 14:10, Thomas Heigl <tho...@umschalt.com>

wrote:

Hi Maxim,

I'm testing against the snapshot now. Will get back to you

shortly.

Thomas

On Wed, Apr 8, 2020 at 2:53 AM Maxim Solodovnik <

solomax...@gmail.com>

wrote:

Hello All,

M5 seems to be broken (deploy has failed more than 10 times

during

my

build attempts)
I have to start another release
Could you please tell when can I start?

On Wed, 8 Apr 2020 at 07:01, Maxim Solodovnik <

solomax...@gmail.com

wrote:

Hello Thomas,

Please test M6-SNAPSHOT (so I don't have to release M5.2 :))))

On Wed, 8 Apr 2020 at 02:39, Thomas Heigl <tho...@umschalt.com

wrote:

Hi Maxim,

That would be great. I want to do some more extensive testing

and

then

deploy M5 into production. ;)

Thomas

On Tue, Apr 7, 2020 at 7:50 PM Maxim Solodovnik <

solomax...@gmail.com>

wrote:

I can pack another release
later this week ...

On Wed, 8 Apr 2020 at 00:48, Thomas Heigl <

tho...@umschalt.com

wrote:

Thanks Sven!

Did your changes make it into the release? Or did they just

miss

it?

Thomas

On Tue, Apr 7, 2020 at 7:43 PM Sven Meier <s...@meiers.net>

wrote:

Hi Thomas,

yes, you're right:

wicketstuff data stores missed some adjustments to the

latest

updates

in

wicket-core.

And SessionQuotaManagingDataStore$DelegatedPage must be

serializable of

course.

I've pushed changes to wicketstuff master.

Thanks
Sven


On 07.04.20 14:14, Thomas Heigl wrote:

And one more thing. There is now a warning logged just

before

serialization:

WARN o.a.w.pageStore.AsynchronousPageStore    : Delegated

page

store

'org.apache.wicket.pageStore.SerializingPageStore' can

not be

asynchronous

On Tue, Apr 7, 2020 at 2:09 PM Thomas Heigl <

tho...@umschalt.com>

wrote:

The cause is the following MetaData entry in the session:

class

org.wicketstuff.datastores.common.SessionQuotaManagingDataStore$1=org.wicketstuff.datastores.common.SessionQuotaManagingDataStore$SizeLimitedData@4090594a

On Tue, Apr 7, 2020 at 1:59 PM Thomas Heigl <

tho...@umschalt.com>

wrote:

Hi Sven,

I just found time to give this a try with Wicket

9.0.0-M5.

There

seem

to

be issues with serialization now.

My new config:

protected IPageStore newCachingStore(IPageStore

pageStore) {

return new CachingPageStore(pageStore, new

InMemoryPageStore(getName(),

MAX_PAGES_CACHED_PER_SESSION));
}
protected IPageStore newPersistentStore() {
final RedissonRedisCache redisCache = new
RedissonRedisCache(redissonClient);
final RedisDataStore redisDataStore = new

RedisDataStore(getName(),

redisCache, new RedisSettings());
return new

SessionQuotaManagingDataStore(redisDataStore,

DATA_STORE_MAX_BYTES_PER_SESSION);
}

This exception is logged after requests:

org.springframework.data.redis.serializer.SerializationException:

Cannot

serialize; nested exception is

org.springframework.core.serializer.support.SerializationFailedException:

Failed to serialize object using DefaultSerializer;

nested

exception

is

java.io.NotSerializableException:

org.wicketstuff.datastores.common.SessionQuotaManagingDataStore$DelegatedPage

at

org.springframework.data.redis.serializer.JdkSerializationRedisSerializer.serialize(JdkSerializationRedisSerializer.java:96)

at

org.springframework.data.redis.core.AbstractOperations.rawHashValue(AbstractOperations.java:185)

at

org.springframework.data.redis.core.DefaultHashOperations.putAll(DefaultHashOperations.java:147)

at

org.springframework.data.redis.core.DefaultBoundHashOperations.putAll(DefaultBoundHashOperations.java:147)

at

org.springframework.session.data.redis.RedisIndexedSessionRepository$RedisSession.saveDelta(RedisIndexedSessionRepository.java:795)

at

org.springframework.session.data.redis.RedisIndexedSessionRepository$RedisSession.save(RedisIndexedSessionRepository.java:783)

at

org.springframework.session.data.redis.RedisIndexedSessionRepository$RedisSession.access$000(RedisIndexedSessionRepository.java:670)

at

org.springframework.session.data.redis.RedisIndexedSessionRepository.save(RedisIndexedSessionRepository.java:398)

at

org.springframework.session.data.redis.RedisIndexedSessionRepository.save(RedisIndexedSessionRepository.java:249)

at

com.myproject.session.InstrumentedFindByIndexNameSessionRepository.save(InstrumentedFindByIndexNameSessionRepository.java:29)

at

java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native

Method)
at

java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at

java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at

java.base/java.lang.reflect.Method.invoke(Method.java:566)

at

org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344)

at

org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198)

at

org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)

at

org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:88)

at

io.micrometer.core.aop.TimedAspect.processWithTimer(TimedAspect.java:105)

at

io.micrometer.core.aop.TimedAspect.timedMethod(TimedAspect.java:94)

at

jdk.internal.reflect.GeneratedMethodAccessor146.invoke(Unknown

Source)

at

java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at

java.base/java.lang.reflect.Method.invoke(Method.java:566)

at

org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:644)

at

org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:633)

at

org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:70)

at

org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)

at

org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:95)

at

org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)

at

org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)

at com.sun.proxy.$Proxy296.save(Unknown Source)
at

org.springframework.session.web.http.SessionRepositoryFilter$SessionRepositoryRequestWrapper.commitSession(SessionRepositoryFilter.java:225)

at

org.springframework.session.web.http.SessionRepositoryFilter$SessionRepositoryRequestWrapper.access$100(SessionRepositoryFilter.java:192)

at

org.springframework.session.web.http.SessionRepositoryFilter.doFilterInternal(SessionRepositoryFilter.java:144)

at

org.springframework.session.web.http.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:82)

at

org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

at

org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

at

org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)

at

org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)

at

org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:666)

at

org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)

at

org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)

at

org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)

at

org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)

at

org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373)

at

org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)

at

org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)

at
org.apache.tomcat.util.net

.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1594)

at
org.apache.tomcat.util.net

.SocketProcessorBase.run(SocketProcessorBase.java:49)

at

java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)

at

java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)

at

org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.base/java.lang.Thread.run(Thread.java:834)
Caused by:

org.springframework.core.serializer.support.SerializationFailedException:

Failed to serialize object using DefaultSerializer;

nested

exception

is

java.io.NotSerializableException:

org.wicketstuff.datastores.common.SessionQuotaManagingDataStore$DelegatedPage

at

org.springframework.core.serializer.support.SerializingConverter.convert(SerializingConverter.java:68)

at

org.springframework.core.serializer.support.SerializingConverter.convert(SerializingConverter.java:35)

at

org.springframework.data.redis.serializer.JdkSerializationRedisSerializer.serialize(JdkSerializationRedisSerializer.java:94)

... 52 common frames omitted
Caused by: java.io.NotSerializableException:

org.wicketstuff.datastores.common.SessionQuotaManagingDataStore$DelegatedPage

Why does Wicket 9 try to serialize the

SessionQuotaManagingDataStore in

the session? Is this intended and does DelegatePage

simply

need to

implement Serializable or shouldn't this be serialized

at

all? In

Wicket 8,

the corresponding PageData wasn't serializable either so

my

guess

would be

that this behavior is not intended.

I'm using the following config for Wicket 8 and there

are no

such

issues:

protected IPageStore newPageStore(IDataStore dataStore)

final ISerializer pageSerializer =
getFrameworkSettings().getSerializer();
return new PerSessionPageStore(pageSerializer,

dataStore,

MAX_PAGES_CACHED_PER_SESSION);
}
protected IDataStore newDataStore() {
final RedissonRedisCache redisCache = new
RedissonRedisCache(redissonClient.get());
final RedisDataStore redisDataStore = new

RedisDataStore(redisCache,

new

RedisSettings());
return new

SessionQuotaManagingDataStore(redisDataStore,

DATA_STORE_MAX_BYTES_PER_SESSION);
}

Best regards,

Thomas

On Sat, Mar 28, 2020 at 10:23 AM Thomas Heigl <

tho...@umschalt.com

wrote:

Thanks Sven!

That looks much better. I'll give it a try as soon as I

can.

Best regards,

Thomas

On Fri, Mar 27, 2020 at 2:23 PM Sven Meier <

s...@meiers.net

wrote:

Hi Thomas,

your question comes at the right time.

I was able to improve the implementation with a new

CachingPageStore:

https://github.com/apache/wicket/blob/8df3528dc44a08b7d375c20e764a3664cd6a5f30/wicket-core/src/main/java/org/apache/wicket/DefaultPageManagerProvider.java#L145

You can now use InMemoryPageStore as a cache too.

Have fun
Sven


On 27.03.20 09:34, Sven Meier wrote:

Hi Thomas,

I thought I covered that usecase, but I will have to

take

look.

Thanks for testing Wicket 9
Sven

On 25.03.20 20:10, Thomas Heigl wrote:

Maybe the same approach could be used as for

InSessionPageStore

that

can be
used as cache and a store:

https://github.com/apache/wicket/commit/894799e01227781be76886b2d1cdb2a424c812e0

On Wed, Mar 25, 2020 at 6:35 PM Thomas Heigl <

tho...@umschalt.com>

wrote:

Hi all,

I just merged our master in our Wicket 9 branch and

ran

into an

issue:

Our current configuration with Wicket 8 looks like

this:

PageStore = PerSessionPageStore
DataStore = RedisDataStore

So the page store keeps the last couple of pages of

session

in

memory

and Redis is used as a persistent store.

I tried to recreate this behavior with Wicket 9:

SessionStore = InMemoryPageStore
PersistentStore = RedisDataStore

This looks correct, but it *does not work* because

InMemoryPage

store

implements AbstractPersistentPageStore and does

*not*

delegate to

the

next store in the chain.

So we basically lost the option to use a memory

page

store in

front

of a
persistent store.

We need this functionality because we are using

Spring

Session and

cannot
use the session as a page store.

Would it be possible to add an InMemory store that

delegates

to

the

next
store in the chain? Or do I have to implement it

myself?

Best regards,

Thomas

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Re: Equivalent for PerSessionPageStore in Wicket 9

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