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Fri, 31 August 2012 11:32

Eclipse User

Hi,

we are facing some performance problems with big data structures.
The objects are cached on the server side. At least we see no sql statements.
But it looks like there is a tramendeous amount of client-server-communication, when we retrieve the objects from the server cache.
I managed to get some improvement by using cdoPrefetch(1), but running through the structure is still very slow.
Prefetching on a higher level was counterproductive, because then every reference is fetched.
How can I configure to eager load only one list?
Can you point me to some documentation about cdo caching and fetch strategies?
By the way, we are using DB Store.

Thanks in advance,

Joe

Re: [CDO] Performance [message #906139 is a reply to message #906087]

Fri, 31 August 2012 13:22

Eclipse User

Am 31.08.2012 17:32, schrieb Joe Sobeos:
> Hi,
>
> we are facing some performance problems with big data structures.
> The objects are cached on the server side. At least we see no sql statements.
> But it looks like there is a tramendeous amount of client-server-communication, when we retrieve the objects from the
> server cache.
Is this caused by the characteristics of your model, e.g., very large datatypes or lists?

> I managed to get some improvement by using cdoPrefetch(1), but running through the structure is still very slow.
> Prefetching on a higher level was counterproductive, because then every reference is fetched.
> How can I configure to eager load only one list?
> Can you point me to some documentation about cdo caching and fetch strategies?
You should start with http://wiki.eclipse.org/CDO/Tweaking_Performance

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

Re: [CDO] Performance [message #906861 is a reply to message #906139]

Sun, 02 September 2012 16:04

Eclipse User

> Is this caused by the characteristics of your model, e.g., very large datatypes or
> lists?

No.
I would say it is caused by the overhead of the client-server-communication.

> You should start with http://wiki.eclipse.org/CDO/Tweaking_Performance

I checked the page, but I did not find a solution to my problem.
How can I configure CDO to fetch a sublist directly with the object?
I don't want to fetch all lists referenced by the object. -> cdoPrefetch seems not to be the solution.

At the moment I iterate through a list of objects. For each object I call cdoPrefetch(1) to get at least the collection loaded at once. But it is still slow even everything is coming from the server cache.

Is there something like fetch=FetchType.EAGER in JPA?

Re: [CDO] Performance [message #906992 is a reply to message #906861]

Mon, 03 September 2012 01:19

Eclipse User

Am 02.09.2012 22:04, schrieb Joe Sobeos:
>> Is this caused by the characteristics of your model, e.g., very large datatypes or lists?
>
> No.
> I would say it is caused by the overhead of the client-server-communication.
I don't see how we can reduce that.

>
>> You should start with http://wiki.eclipse.org/CDO/Tweaking_Performance
>
> I checked the page, but I did not find a solution to my problem.
> How can I configure CDO to fetch a sublist directly with the object?
http://wiki.eclipse.org/CDO/Tweaking_Performance#Prefetching_Target_Objects_Automatically_.E2.80.93_CDORevisionPrefetchingPolicy

But that applies to all lists of an object.

> I don't want to fetch all lists referenced by the object. -> cdoPrefetch seems not to be the solution.
Prefetching selected lists is not possible with CDO as of now.

> At the moment I iterate through a list of objects. For each object I call cdoPrefetch(1) to get at least the
> collection loaded at once. But it is still slow even everything is coming from the server cache.
>
> Is there something like fetch=FetchType.EAGER in JPA?
I don't know JPA exactly but CDO doesn't support per-feature configuration of load characteristics.

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

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