You know, that's just not what I'm seeing. I even wrote a little
test app.
Criteria c = HibHelper.getSession().createCriteria("core.User");
c.setCacheable(true);
List l = c.list();
// the above executes a single query to fill the cache
// I get one and only one query in my SQL trace
c = HibHelper.getTransientTempSession().createCriteria("core.User");
// a new criteria on a new session
c.setCacheable(true);
l = c.list();
// the above should hit the cache
// lo and behold, we get 1,000 individual selects
// as every single key from the original select is iteratively
// fetshed one at a time
Perhaps I have something configured wrong?
The point in my mapping where I enable the cache:
<class name="core.Person" table="person" dynamic-update="true">
<cache usage="read-write" />
/// blah blah blah
</class>
The point in my hibernate configuration where I enable ehcache:
<property name="hibernate.cache.use_query_cache">true</property>
My ehcache.xml where I set a nice spiffy default cache:
<defaultCache
maxElementsInMemory="10000"
eternal="false"
timeToIdleSeconds="1200"
timeToLiveSeconds="1200"
overflowToDisk="false"
diskPersistent="false"
diskExpiryThreadIntervalSeconds="120"
/>
Is there some additional parm I have to set to enable the L2 object
cache here? Because from what I'm seeing here, the keys are getting cached,
but the object themselves are not, leading to the aforementioned 1000
selects by key (which is about 200X worse than just one massive select).
--- Pat
> -----Original Message-----
> From: Konstantin Ignatyev [mailto:[EMAIL PROTECTED]
> Sent: Saturday, September 24, 2005 8:06 PM
> To: Tapestry users
> Subject: RE: Hibernate session model
>
> Query cache is slightly different thing than
> Hibernate's 2L cache.
> L2 cache holds objects and L2 cache will supply
> objects by keys in Query cache.
>
> --- Patrick Casey <[EMAIL PROTECTED]> wrote:
>
> >
> > Henri,
> >
> > Where are you getting your information from?
> > According to my copy of
> > Hibernate in action (pp 291 Secion 7.6.3).
> >
> > "Note that the query cache does *not* cache the
> > entities returning
> > in the query reslut set, just the identifier
> > values."
> >
> > Am I missing something here?
> >
> > --- Pat
> >
> > > -----Original Message-----
> > > From: Henri Dupre [mailto:[EMAIL PROTECTED]
> > > Sent: Saturday, September 24, 2005 9:12 AM
> > > To: Patrick Casey
> > > Cc: Tapestry users
> > > Subject: Re: Hibernate session model
> > >
> > > On 9/23/05, Patrick Casey <[EMAIL PROTECTED]>
> > wrote:
> > > >
> > > > >
> > > > > I rather have a DB Query than a lazy
> > exception. And not for every
> > > call!
> > > > > The hibernate cache is here for that.
> > > >
> > > > If memory serves, the hibernate cache caches
> > keys, not objects.
> > >
> > > This is not true. The hibernate second level cache
> > is a map with <key,
> > > object>,
> > > If your key is found in the cache then it
> > retrieves the object (memory
> > > or file depending on your cache configuration).
> > > We achieve a high performance by having it
> > properly configured on a
> > > per-class basis even with complex queries.
> > >
> > > Henri.
> > >
> > >
> >
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> >
> >
> >
> >
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