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From "Yong Liang Li" <liyo...@cn.ibm.com>
Subject Re: A better way to add/remove hold in CMIS 1.1?
Date Thu, 04 Feb 2016 01:58:21 GMT
Florian,

Thanks for your response. In my case, our content server implements hold as
relationship like folder. There is no hold list stored for each of the
objects in content server. We need to query the relationships related to
the object to get all the holds. If a whole list is updated, we need to
query out all the existing holds and compare the two list.

In the most cases, from business' perspective, add/remove hold is typical
usage scenario because a specific user does not care much about which hold
is currently on a specific object. What he/she cares is whether a new hold
should be added or whether an existing hold should be removed. One
workaround that is under discussion is to enforce user to add prefix like
AddHold_ or RemoveHold_ to the object ids that the user want to update in
the list. This way, CMIS server can easily understand the intention of the
user and no need to do a retrieve and compare.

Unfortunately, our content server has no support to change token.


Best Regards,

Mike Li(李永亮)
IBM Content Manager RM Development
Tel:(86-10)82453403 Fax:(86-10)58851920 Tie-line: 905-3403
liyongl@cn.ibm.com



From:	Florian Müller <fmui@apache.org>
To:	dev@chemistry.apache.org
Cc:	Srinivas Nv Gannavarapu <srinivas.gannavarapu@in.ibm.com>,
            Randy Richardt <rrichar@us.ibm.com>, Jay Brown
            <jay.brown@us.ibm.com>, Yong Liang Li/China/IBM@IBMCN
Date:	2016/02/03 16:57
Subject:	Re: A better way to add/remove hold in CMIS 1.1?



Hi Mike,

I hope I've some answers for you.

Re a) Holds are stored as a multi-value property. CMIS only allows
retrieving and updating multi-value properties as a whole. There is no
support for partial retrieval or partial update.
But if a client doesn't modify the list of holds, it shouldn't send it
to the server. Hence, there is no need for the server to retrieve the
list of holds all the time.
Do you except a frequent change of holds on an object? In the use cases
I know, holds are not updated very often.

Re b) That shouldn't happen if your server implements change tokens
correctly. Change tokens are supposed to prevent lost updates.


- Florian



> Hi all,
>
> In the current CMIS 1.1 spec, hold is supported by secondary type.
> Specifically, the user can add/remove ids from cmis:hold.rm_holdIds to
> add/remove holds. There are two major issues here.
>    a) The user need to firstly retrieve out the whole hold list before
> the
>    user can add/remove hold. The list might be a big one depends on
>    business needs. In CMIS server side implementation, we need to
> firstly
>    retrieve out this list from content server and compare it to the
> list in
>    the update request. So that we get to know which one should be
>    added/removed. Even though there is no change in this list, we still
>    need to do the retrieve and compare practice in each checkin. This
> will
>    not perform well.
>    b) May result in inconsistences in consequent updates. For example,
> user
>    A is trying to add a hold, so it pass the original list plus the one
>    that it wants to add hold. Now user B wants to add another hold. If
> user
>    B's original list had been retrieved out before user A completed the
>    update, then user A's update will be overwritten by user B's update,
>    unintentionally.
>
>
> So, I wonder whether there is a better way to add/remove holds without
> going through the retrieve and compare logic in an update(checkin).
> Thanks
> in advance!
>
>
> Best Regards,
>
> Mike Li(李永亮)
> IBM Content Manager RM Development
> Tel:(86-10)82453403 Fax:(86-10)58851920 Tie-line: 905-3403
> liyongl@cn.ibm.com


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