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[CDO] Using server-side EObjects [message #849970] Thu, 19 April 2012 16:21 Go to next message
Alain Picard is currently offline Alain PicardFriend
Messages: 266
Registered: July 2009
Senior Member
Hi,

I see that bug 273562 is now closed and that we have server-side EObjects.

In a different forum post, Eike stated that "ServerCDOView is a very
restricted implementation of CDOView. Many operations are not supported
in this light weight kind of view."

Can anyone elaborate a bit on what is supported and what is not. More
specifically in regards to transaction. I see a Transaction class but it
doesn't inherit from CDOServerView. What is the story?

Thanks for clarifying the support of this exciting feature.

Cheers,
Alain
Re: [CDO] Using server-side EObjects [message #850038 is a reply to message #849970] Thu, 19 April 2012 17:50 Go to previous messageGo to next message
Eike Stepper is currently offline Eike StepperFriend
Messages: 6682
Registered: July 2009
Senior Member
Hi Alain,

EObjects on the server have always been possible by opening a normal CDOSession on the server. From there you can do
everything that is possible on clients, too.

In some scenarios that only require on-the-fly (i.e. without separate revision caching) read access to EObjects on the
server (e.g. IQueryHandlers, ObjectWriteAccessHandler, etc...) we've implemented optimized ServerCDOView and
ServerCDOSession classes. See the CDOServerUtil.openView() methods.

The unsupported functions can mostly be deduced from the methods in CDOViewImpl.java, namely:

- write access (due to the lack of ServerCDOTransaction)
- explicit (read) locking
- invalidation (EMF change notifications)

Cheers
/Eike

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



Am 19.04.2012 18:21, schrieb Alain Picard:
> Hi,
>
> I see that bug 273562 is now closed and that we have server-side EObjects.
>
> In a different forum post, Eike stated that "ServerCDOView is a very restricted implementation of CDOView. Many
> operations are not supported in this light weight kind of view."
>
> Can anyone elaborate a bit on what is supported and what is not. More specifically in regards to transaction. I see a
> Transaction class but it doesn't inherit from CDOServerView. What is the story?
>
> Thanks for clarifying the support of this exciting feature.
>
> Cheers,
> Alain


Re: [CDO] Using server-side EObjects [message #850049 is a reply to message #850038] Thu, 19 April 2012 18:04 Go to previous messageGo to next message
Alain Picard is currently offline Alain PicardFriend
Messages: 266
Registered: July 2009
Senior Member
Hi Eike,

We mostly use the JVMConnector so I believe that it is essentially
equivalent to what you are referring to.

But the beauty that I was seeing in the server-side EObject was the fact
that from what I can see, it doesn't involve any marshalling and
un-marshalling of the data, just straight object creation which with
large amount of data does have at some point a significant impact on the
overall performance.

Cheers,
Alain


On 4/19/2012 1:50 PM, Eike Stepper wrote:
> Hi Alain,
>
> EObjects on the server have always been possible by opening a normal
> CDOSession on the server. From there you can do everything that is
> possible on clients, too.
>
> In some scenarios that only require on-the-fly (i.e. without separate
> revision caching) read access to EObjects on the server (e.g.
> IQueryHandlers, ObjectWriteAccessHandler, etc...) we've implemented
> optimized ServerCDOView and ServerCDOSession classes. See the
> CDOServerUtil.openView() methods.
>
> The unsupported functions can mostly be deduced from the methods in
> CDOViewImpl.java, namely:
>
> - write access (due to the lack of ServerCDOTransaction)
> - explicit (read) locking
> - invalidation (EMF change notifications)
>
> Cheers
> /Eike
>
> ----
> http://www.esc-net.de
> http://thegordian.blogspot.com
> http://twitter.com/eikestepper
>
>
>
> Am 19.04.2012 18:21, schrieb Alain Picard:
>> Hi,
>>
>> I see that bug 273562 is now closed and that we have server-side
>> EObjects.
>>
>> In a different forum post, Eike stated that "ServerCDOView is a very
>> restricted implementation of CDOView. Many operations are not
>> supported in this light weight kind of view."
>>
>> Can anyone elaborate a bit on what is supported and what is not. More
>> specifically in regards to transaction. I see a Transaction class but
>> it doesn't inherit from CDOServerView. What is the story?
>>
>> Thanks for clarifying the support of this exciting feature.
>>
>> Cheers,
>> Alain
Re: [CDO] Using server-side EObjects [message #850068 is a reply to message #850049] Thu, 19 April 2012 18:31 Go to previous messageGo to next message
Eike Stepper is currently offline Eike StepperFriend
Messages: 6682
Registered: July 2009
Senior Member
Am 19.04.2012 20:04, schrieb Alain Picard:
>
> Hi Eike,
>
> We mostly use the JVMConnector so I believe that it is essentially equivalent to what you are referring to.
>
> But the beauty that I was seeing in the server-side EObject was the fact that from what I can see, it doesn't involve
> any marshalling and un-marshalling of the data, just straight object creation which with large amount of data does
> have at some point a significant impact on the overall performance.
Yes. I forgot to explicitely mention this as a consequence of not caching the server revisions again in a session cache.

Cheers
/Eike

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


>
> Cheers,
> Alain
>
>
> On 4/19/2012 1:50 PM, Eike Stepper wrote:
>> Hi Alain,
>>
>> EObjects on the server have always been possible by opening a normal
>> CDOSession on the server. From there you can do everything that is
>> possible on clients, too.
>>
>> In some scenarios that only require on-the-fly (i.e. without separate
>> revision caching) read access to EObjects on the server (e.g.
>> IQueryHandlers, ObjectWriteAccessHandler, etc...) we've implemented
>> optimized ServerCDOView and ServerCDOSession classes. See the
>> CDOServerUtil.openView() methods.
>>
>> The unsupported functions can mostly be deduced from the methods in
>> CDOViewImpl.java, namely:
>>
>> - write access (due to the lack of ServerCDOTransaction)
>> - explicit (read) locking
>> - invalidation (EMF change notifications)
>>
>> Cheers
>> /Eike
>>
>> ----
>> http://www.esc-net.de
>> http://thegordian.blogspot.com
>> http://twitter.com/eikestepper
>>
>>
>>
>> Am 19.04.2012 18:21, schrieb Alain Picard:
>>> Hi,
>>>
>>> I see that bug 273562 is now closed and that we have server-side
>>> EObjects.
>>>
>>> In a different forum post, Eike stated that "ServerCDOView is a very
>>> restricted implementation of CDOView. Many operations are not
>>> supported in this light weight kind of view."
>>>
>>> Can anyone elaborate a bit on what is supported and what is not. More
>>> specifically in regards to transaction. I see a Transaction class but
>>> it doesn't inherit from CDOServerView. What is the story?
>>>
>>> Thanks for clarifying the support of this exciting feature.
>>>
>>> Cheers,
>>> Alain
>


Re: [CDO] Using server-side EObjects [message #871118 is a reply to message #850038] Thu, 10 May 2012 23:44 Go to previous messageGo to next message
Alain Picard is currently offline Alain PicardFriend
Messages: 266
Registered: July 2009
Senior Member
Hi Eike,

I am seeing the "Not yet supported" embedded session and protocol and it
does look a lot like what we're looking for, i.e. to use CDO server side
without the overhead of Net4j.

Am I mistaken?

If not, any guidance on why this is not completed and/or pitfalls in
expanding the implementation.

Cheers,
Alain

On 4/19/2012 1:50 PM, Eike Stepper wrote:
> Hi Alain,
>
> EObjects on the server have always been possible by opening a normal
> CDOSession on the server. From there you can do everything that is
> possible on clients, too.
>
> In some scenarios that only require on-the-fly (i.e. without separate
> revision caching) read access to EObjects on the server (e.g.
> IQueryHandlers, ObjectWriteAccessHandler, etc...) we've implemented
> optimized ServerCDOView and ServerCDOSession classes. See the
> CDOServerUtil.openView() methods.
>
> The unsupported functions can mostly be deduced from the methods in
> CDOViewImpl.java, namely:
>
> - write access (due to the lack of ServerCDOTransaction)
> - explicit (read) locking
> - invalidation (EMF change notifications)
>
> Cheers
> /Eike
>
> ----
> http://www.esc-net.de
> http://thegordian.blogspot.com
> http://twitter.com/eikestepper
>
>
>
> Am 19.04.2012 18:21, schrieb Alain Picard:
>> Hi,
>>
>> I see that bug 273562 is now closed and that we have server-side
>> EObjects.
>>
>> In a different forum post, Eike stated that "ServerCDOView is a very
>> restricted implementation of CDOView. Many operations are not
>> supported in this light weight kind of view."
>>
>> Can anyone elaborate a bit on what is supported and what is not. More
>> specifically in regards to transaction. I see a Transaction class but
>> it doesn't inherit from CDOServerView. What is the story?
>>
>> Thanks for clarifying the support of this exciting feature.
>>
>> Cheers,
>> Alain
Re: [CDO] Using server-side EObjects [message #871477 is a reply to message #871118] Mon, 14 May 2012 05:10 Go to previous message
Eike Stepper is currently offline Eike StepperFriend
Messages: 6682
Registered: July 2009
Senior Member
Alain Picard wrote on Thu, 10 May 2012 19:44
Hi Eike,

I am seeing the "Not yet supported" embedded session and protocol and it
does look a lot like what we're looking for, i.e. to use CDO server side
without the overhead of Net4j.

Am I mistaken?

If not, any guidance on why this is not completed and/or pitfalls in
expanding the implementation.


The CDOEmbeddedProtocol has never been finished because it turned out that there's still too much core logic contained in the Net4j-based CDOClientProtocol and, if at all, too few users complained about the JVMConnector-based embedding.

Cheers
/Eike


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