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From Andrus Adamchik <and...@objectstyle.org>
Subject Re: Exception when caching a SelectQuery with prefetching [WAS: Caching]
Date Thu, 20 May 2010 08:14:50 GMT
One thing to keep in mind here is that OSQueryCacheFactory is not  
tested with persistent cache... It works perfect with in-memory cache,  
but I always thought that persisting the data that is sort of already  
persisted in the DB doesn't buy us much, so that scenario never got  
any attention. E.g. I wouldn't be surprised if de-serialization of the  
cache causes even more issues.

Andrus


On May 20, 2010, at 10:03 AM, Andrey Razumovsky wrote:

> Looks like a bug. Could you please open a ticket?
>
> 2010/5/20 Gary Jarrel <garyjarrel@gmail.com>
>
>> Hi,
>> I managed to get the cache issue described below resolved, my error
>> with the DataContextFilter that I was using and it was overwriting  
>> the
>> modeler configuration when initializing shared config.
>>
>> I've ran into another issue with the following code:
>>
>> SelectQuery q = proto.queryWithParameters(params);
>> q.addPrefetch(RichProduct.MANUFACTURER_PROPERTY);
>> q.addPrefetch(RichProduct.RAW_PRODUCT_PROPERTY);
>> q.setCacheStrategy(QueryCacheStrategy.SHARED_CACHE);
>> q.setCacheGroups("products");
>>
>> Upon execution of this query I get the following exception:
>>
>> ERROR  
>> com.opensymphony.oscache.base.algorithm.AbstractConcurrentReadCache
>> [oscache] Exception persisting RichProduct/subCategory =
>> <ObjectId:SubCategory, category_id=1,
>> id=1>/categoryName/subCategoryName/cost
>> com.opensymphony.oscache.base.persistence.CachePersistenceException:
>> Unable to write
>> '/tmp/cache/application/0/0/5/005126BC80FABAA4C582919EDF0B9304.cache'
>> in the cache. Exception: java.io.NotSerializableException, Message:
>> org.apache.cayenne.access.ListWithPrefetches
>>       at
>> com 
>> .opensymphony 
>> .oscache 
>> .plugins 
>> .diskpersistence 
>> .AbstractDiskPersistenceListener 
>> .store(AbstractDiskPersistenceListener.java:376)
>>       at
>> com 
>> .opensymphony 
>> .oscache 
>> .plugins 
>> .diskpersistence 
>> .AbstractDiskPersistenceListener 
>> .store(AbstractDiskPersistenceListener.java:238)
>>
>> <rest of stack trace removed>
>>
>> If I however remove the prefetches then the caching works fine.
>>
>> Looking at the source code for ListWithPrefetches it does not
>> implement Serializable, could this be the reason for it, or am I
>> missing something!
>>
>> Thank you
>>
>> Gary
>>
>> On Wed, May 19, 2010 at 6:17 PM, Gary Jarrel <garyjarrel@gmail.com>  
>> wrote:
>>>
>>> Hi Guys,
>>> I seem to full of questions today!
>>> In the modeler I've got  
>>> org.apache.cayenne.cache.OSQueryCacheFactory for
>> Query Cache Factory, 5000 objects and using shared cache.
>>> I can see OSCache initializing in the logs and everything appears  
>>> to be
>> fine.
>>> However when I try to get the cache from the ObjectContext like so:
>>> QueryCache cache = ((BaseContext)  
>>> getObjectContext()).getQueryCache();
>>> The cache that is being returned is
>> the org.apache.cayenne.cache.MapQueryCache
>>> I've traced the calls and can see that the call got  
>>> getQueryCache() goes
>> to MapQueryCacheFactory despite the fact that the modeler
>> specifies OSQueryCacheFactory
>>> Am I doing something wrong here?
>>> Thank you
>>> Gary
>>
>
>
>
> -- 
> Andrey


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