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Hibernate version: 2.1.8

Hi

I’ve got a ”funny” problem. To simplify things I’ve used the objects Dog and Cat in the following example.

A Dog has a reference to a parent Dog, and a set of Cats.
A Cat has a set of Dog’s.

When I load my application, all Cat’s and Dog’s are loaded from the DB and stored in two lists (List dogs and List cats).
On each Dog object, I have a list of children generated by a method:
Public List getChildrenByParentPk(long pk).

Here is the mapping:

---------------------------------------------------------
Dog

<many-to-one name=”parent” class=”Dog” column=”dog_fk”/>

<set name=”cats” table=”cat_dog_rel”>
<key column=”dog_fk”/>
<many-to-many class=”Cats” column=”cat_fk”/>
</set>

Cat

<set name=”dogs” table=”cat_dog_rel”>
<key column=”cat_fk”/>
<many-to-many class=”Dogs” column=”dog_fk”/>
</set>
---------------------------------------------------------


The problem:
It takes a LONG time to load the children – approx. 40 seconds pr. Dog (which is pretty annoying if I have 1000 Dog’s). However, if I remove the “cats” set from the Dog mapping, it takes under 1 second.

I’ve tried to change some settings in hibernate like: cache-settings and hibernate.max_fetch_depth, but with the same result.

Are there anyone else out there who’ve had similar problems with this combination of hierarchy and bidirectional sets?

multple options...
a. use lazy="true"
b. check the indexes. We had the problem that when there wasn't proper indexes defined, the queries were taking long time
c. use batch-size="100" say.