I am trying to get a handle on what I should be able to achieve.
Can someone give me some idea of the metrics I should be able to get
optimistically when persisting an object that has a child list with 20,000 child
objects and 20,000 grandchildren? (one-to-one child -> grandchild)
Can I reasonably expect to get this done in under a minute?
I think that would work out at a rate of about 1.5 milliseconds per object.
Thanks
Adam
Adam Hardy on 11/06/10 17:34, wrote:
I have performance problems with large lists of beans due to the base
class I am using for my entities.
This is slightly non-OpenJPA specific, so I hope nobody minds, but it is
Friday afternoon so I'm hoping you give me a bit of slack here.
The problem arises when I start building lists with over 10,000 items on
a parent class.
The trouble is in the base class for the entities, which is quite clever
(but obviously not clever enough) and it has non-facile equals() and
hashcode() algorithms which make use of reflection. It's here that the
slow-down comes.
When I link the child with a parent that already has 10,000 children,
the equals() method is called by ArrayList before the new child is
placed in the index.
As far as I can tell I have a couple of options.
(1) ditch the reflection-based equals method and hard-code an equals
method.
(2) don't use ArrayList but find a Collection-based class that uses
hashes or similar to identify items instead of equals. This is just
speculation - perhaps there is no such thing or it wouldn't help anyway:
- would a collection using hashes caches the hashes of the items
already indexed?
- would such a collection be persistable?
If anyone has been in this situation before, or has an idea about it ,
I'd really appreciate the help.
Regards
Adam
