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Re: Re: [eclipselink-users] Caching read-all queries
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Thanks Zazar, I'm always interested in good eclipselink related blogs.
./tch
On Tue, Jun 1, 2010 at 3:09 PM, Zarar Siddiqi <zarars@xxxxxxxxx> wrote:
> For those interested, I've written a blog entry on how I integrated
> this with EhCache:
>
> http://weblogs.java.net/blog/zarar/archive/2010/05/31/integrating-eclipsellink-ehcache-cache-readall-and-native-queries
>
>
>
> On Tue, Jun 1, 2010 at 9:29 AM, James Sutherland <jamesssss@xxxxxxxxx> wrote:
>>
>> No, you will only see SQL if the SQL is sent to the database.
>>
>> By default any Query will access the database, where as any find()
>> operation, or ToOne relationship access will first check the object cache.
>>
>> On any primary key (Id) Query, you can configure it using the
>> "eclipselink.cache-usage" query hint to "CheckCacheByPrimaryKey". If the
>> Query returns a single object, you can use "CheckCacheThenDatabase" (you
>> can't use this for a result list as EclipseLink can not know if it has them
>> all in the cache). If you know you have all the objects in the cache, you
>> can use, "CheckCacheOnly".
>>
>> EclipseLink also allows any "NamedQuery" to cache its results. If you
>> re-execute the same NamedQuery with the same parameters, you will get a
>> query cache hit. The query cache is configured on the query using the query
>> hint, "eclipselink.query-results-cache"="true".
>>
>> See,
>> http://www.eclipse.org/eclipselink/api/2.0.1/org/eclipse/persistence/config/QueryHints.html
>>
>>
>> tch wrote:
>>>
>>> I believe even if EL is hitting the cache you'll still see the SQL in the
>>> logs.
>>>
>>> ./tch
>>>
>>>
>>> On Wed, May 19, 2010 at 8:53 PM, Zarar Siddiqi <zarars@xxxxxxxxx> wrote:
>>>
>>>> I've already tried the following:
>>>>
>>>> Session session =
>>>> JpaHelper.getServerSession(em.getEntityManagerFactory());
>>>>
>>>> ReadAllQuery q = new ReadAllQuery(Person.class);
>>>> q.setJPQLString("SELECT OBJECT(p) FROM Person p");
>>>> q.addArgument("1");
>>>> q.addArgument("3");
>>>> List args = new ArrayList();
>>>> args.add(activityCode);
>>>> q.cacheQueryResults();
>>>> q.cacheStatement();
>>>> q.setQueryResultsCachePolicy(new QueryResultsCachePolicy(new
>>>> TimeToLiveCacheInvalidationPolicy(60000));
>>>> List list = session.executeQuery(q, args);
>>>>
>>>> Despite this, it still prints the SQL twice in the logs on successive
>>>> calls. This is based on the example shown here:
>>>>
>>>>
>>>> http://wiki.eclipse.org/EclipseLink/Examples/JPA/ORMQueries#A_Simple_ReadAllQuery_Using_JPQL
>>>>
>>>>
>>>>
>>>>
>>>> On Wed, May 19, 2010 at 6:05 PM, Zarar Siddiqi <zarars@xxxxxxxxx> wrote:
>>>> > I'm using 1.2 and have a couple cache related questions.
>>>> >
>>>> > Do read-all queries (ones using getResultList()) always hit the
>>>> database?
>>>> >
>>>> > As I understand the docs, the "CheckCacheThenDatabase" hit only
>>>> > applies to read-object queries (ones using getSingleResult()). In my
>>>> > app, I have a ton of queries that are candidates for caching, but they
>>>> > all use getResultList(). I've set an @Cache(expiry=60000) annotation
>>>> > on those entities and when I execute them, I keep seeing the queries
>>>> > printed in the logs.
>>>> >
>>>> > To me, this isn't the greatest behaviour since I'm executing the exact
>>>> > same query with the exact same parameters. Shouldn't EclipseLink have
>>>> > a way of optimizing this?
>>>> >
>>>> > Thanks,
>>>> > Zarar
>>>> >
>>>>
>>>>
>>>>
>>>> --
>>>> Zarar Siddiqi
>>>> 416-737-9024
>>>
>>>
>>
>>
>> -----
>> http://wiki.eclipse.org/User:James.sutherland.oracle.com James Sutherland
>> http://www.eclipse.org/eclipselink/
>> EclipseLink , http://www.oracle.com/technology/products/ias/toplink/
>> TopLink
>> Wiki: http://wiki.eclipse.org/EclipseLink EclipseLink ,
>> http://wiki.oracle.com/page/TopLink TopLink
>> Forums: http://forums.oracle.com/forums/forum.jspa?forumID=48 TopLink ,
>> http://www.nabble.com/EclipseLink-f26430.html EclipseLink
>> Book: http://en.wikibooks.org/wiki/Java_Persistence Java Persistence
>> --
>> View this message in context: http://old.nabble.com/Caching-read-all-queries-tp28614962p28741730.html
>> Sent from the EclipseLink - Users mailing list archive at Nabble.com.
>>
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>> eclipselink-users@xxxxxxxxxxx
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>>
>
>
>
> --
> Zarar Siddiqi
> 416-737-9024
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