[infinispan-dev] Fwd: CloudCacheStore Bug

Thu Feb 4 09:06:43 EST 2010

Manik, it is is asynchronous, by default.

So I definitely think there is something rotten in the kingdom of Eviction.
Since :
1) Eviction is fired in a new thread (I can disable this, no effect)
2) It removes entries from the datacontainer
3) While the datacontainer is 'maybe' asynchronously trying to write entries
in the cachestore (using multiple threads!!)

It makes a lot of threads, acting on the same data, at the same time...
perfect for race conditions.

Right now, I am loosing data - it is LOST (not written to the cachestore and
not available in the datacontainer)

So I think that somehow, entries are evicted from the datacontainer... and
the updates to the cachestore are lost somewhere.

I am digging a lot through the code but the good news is that it is very
easy to reproduce, use a config like this (note the eviction stuff) :

<?xml version="1.0" encoding="UTF-8"?>

<infinispan xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="urn:infinispan:config:4.0">
<global>
<transport
transportClass="org.infinispan.remoting.transport.jgroups.JGroupsTransport">
<properties>
<property name="configurationFile" value="jgroups.xml" />
</properties>
</transport>

</global>

<namedCache name="qi4j">
<transaction
transactionManagerLookupClass="org.infinispan.transaction.lookup.DummyTransactionManagerLookup"
/>
<clustering mode="distribution">
<l1 enabled="true" lifespan="100000" />
<hash numOwners="1" rehashRpcTimeout="120000" />
</clustering>

<loaders passivation="false" shared="true" preload="false">

<loader class="org.infinispan.loaders.file.FileCacheStore"
fetchPersistentState="false" ignoreModifications="false"
purgeOnStartup="true" purgeSynchronously="true">
<properties>
<property name="location" value="/tmp" />
</properties>
<async enabled="true" threadPoolSize="1" />
</loader>

</loaders>
 <deadlockDetection enabled="true" spinDuration="1000"></deadlockDetection>

<eviction strategy="FIFO" wakeUpInterval="1000" maxEntries="2" />

<unsafe unreliableReturnValues="true" />

</namedCache>
</infinispan>

I don't know if it is related to transactions... I will now try to fire
eviction manually, as a workaround.

Something that bothers me is the lack of transactional eviction... is it
difficult to make it transactional ? And then commit the whole transaction
to the cachestore and after completion only, delete the entries from the
datacontainer ??

Looks like a design issue ? WDYT ?

Cheers,

Phil

On Thu, Feb 4, 2010 at 10:44 AM, Manik Surtani <manik at jboss.org> wrote:

> That is strange since there is no correlation between eviction and the
> synchronicity of cache stores.  Have you got a reproducible test for this?
>
> Cheers
> Manik
>
> On 3 Feb 2010, at 18:37, Philippe Van Dyck wrote:
>
> Thanks Manik,
>
> I have a another problem with eviction, it seems to destroy cache entries,
> *only when I use async*.
>
> Of course, all updates are transactional.
>
> Where should I search for clues ? Any idea ?
>
> Here is my config:
>
> <?xml version="1.0" encoding="UTF-8"?>
>
> <infinispan xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>  xmlns="urn:infinispan:config:4.0">
> <global>
> <transport
>
> transportClass="org.infinispan.remoting.transport.jgroups.JGroupsTransport">
> <properties>
>  <property name="configurationFile" value="jgroups.xml" />
> </properties>
>  </transport>
>
> </global>
>
> <namedCache name="qi4j">
>  <transaction
> transactionManagerLookupClass="org.infinispan.transaction.lookup.DummyTransactionManagerLookup"
> />
>  <clustering mode="distribution">
> <l1 enabled="true" lifespan="100000" />
>  <hash numOwners="1" rehashRpcTimeout="120000" />
> </clustering>
>
> <loaders passivation="false" shared="true" preload="false">
>
> <loader class="org.infinispan.loaders.file.FileCacheStore"
>  fetchPersistentState="false" ignoreModifications="false"
> purgeOnStartup="true">
>  <properties>
> <property name="location" value="/tmp" />
>  </properties>
> <async enabled="true" threadPoolSize="3" />
>  </loader>
>
> </loaders>
>  <deadlockDetection enabled="true"
> spinDuration="1000"></deadlockDetection>
>
> <eviction strategy="FIFO" wakeUpInterval="1000" maxEntries="10" />
>
> <unsafe unreliableReturnValues="true" />
>
> </namedCache>
> </infinispan>
>
>
> phil
>
>
>
> On Wed, Feb 3, 2010 at 6:42 PM, Manik Surtani <manik at jboss.org> wrote:
>
>> Ugh, good point.  I thought the unit tests would have trapped a dumb-ass
>> mistake like this.
>>
>> The reason for transforming the name of the bucket is that we usually use
>> hashcodes as the bucket name, which can take Integer.MIN_VALUE to
>> Integer.MAX_VALUE.  These are then translated into Strings, and this becomes
>> the name of the storage unit, e.g., 12345.bucket in the FileCacheStore.  Now
>> filesystems are happy to accept a -12345.bucket but certain cloud storage
>> providers barf when encountering the '-' character.  Hence the
>> transformation to A12345.bucket in some cases.
>>
>> Cheers
>> Manik
>>
>> PS: pushing up a new snapshot as I type, containing this fix + lower
>> verbosity on eviction-related lock timeouts.
>>
>> On 3 Feb 2010, at 17:16, Philippe Van Dyck wrote:
>>
>> And BTW, why do it ?
>>
>> p
>>
>> ---------- Forwarded message ----------
>> From: Philippe Van Dyck <pvdyck at gmail.com>
>> Date: Wed, Feb 3, 2010 at 6:15 PM
>> Subject: CloudCacheStore Bug
>> To: infinispan -Dev List <infinispan-dev at lists.jboss.org>
>>
>>
>> Hi all,
>>
>> there is a bug in CloudCacheStore that makes me feel like I am the only
>> one using it ;-)
>>
>> in CR4 : if you change the "-" sign to "A" in getBucketName ... you need
>> to do the opposite somewhere (or call it every time) ;-)
>>
>> WDYT ?
>>
>> p
>>
>> _______________________________________________
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>>
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>>
>>
>>  --
>> Manik Surtani
>> manik at jboss.org
>> Lead, Infinispan
>> Lead, JBoss Cache
>> http://www.infinispan.org
>> http://www.jbosscache.org
>>
>>
>>
>>
>>
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>> https://lists.jboss.org/mailman/listinfo/infinispan-dev
>>
>
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>
> --
> Manik Surtani
> manik at jboss.org
> Lead, Infinispan
> Lead, JBoss Cache
> http://www.infinispan.org
> http://www.jbosscache.org
>
>
>
>
>
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