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Date: Wed, 03 Feb 2016 09:56:39 +0100
From: =?UTF-8?Q?Florian_M=C3=BCller?= <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 <liyongl@cn.ibm.com>
Subject: Re: A better way to add/remove hold in CMIS 1.1?
In-Reply-To: <201602030826.u138QWGI007232@d23av03.au.ibm.com>
References: <201602030826.u138QWGI007232@d23av03.au.ibm.com>
Message-ID: <ea767cf42fb9cc73f0c6a7ab918fcfc5@jpberlin.de>
User-Agent: RoundCube Webmail

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