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Date: Thu, 1 Oct 2009 10:58:32 +0300
Message-ID: <c7fc82820910010058p1a3d3e9ejf6428104d5b5cb04@mail.gmail.com>
Subject: Re: Deleting user from access pool
From: Vassil Dichev <vdichev@apache.org>
To: esme-dev@incubator.apache.org
Content-Type: text/plain; charset=ISO-8859-1

There are counterexamples- when you send out an email, it's in the
inbox of the people you have sent it to and you cannot delete it. When
you send a message in an instant messaging client, you cannot get it
back. In the context of JIRA, the item can still change after
permission is denied to you, while the message cannot be reedited in
ESME.

I'm with Dick here. The performance problem is that the stream of
messages is updated in near real-time and any deleted messages will
cause a cascade of changes across the inboxes of all users who have
linked this message.

I think we discussed deleting messages before, not in the context of
this pool, and David strongly favored the opinion that messages should
be immutable- once they're sent, that's it. Deleting messages also
poses security/consistency issues with possible federation scenarios,
which David intended to implement.

There are many many other inconsistency issues which could arise if we
start deleting messages. Take for example, resending. If a resent
message is deleted, do you delete it from the inboxes of all your
followers? And if it's a popular resent message, do you delete it from
the stats actor? Do you reevaluate all the statistics for resent
messages then? What if the message contains tags, do you reevaluate
the tag cloud? What if it contains links, which are in the popular
links stats? What if the message is part of a conversation, do you
delete the whole conversation?

So in the end, the immutability of messages and timelines is already
deeply ingrained in the ESME architecture and is not subject to
change- even if we decide that it's wise to do so, which I think it's
not. It's far from a trivial change.

Vassil


On Thu, Oct 1, 2009 at 10:37 AM, Xuefeng Wu <benewu@gmail.com> wrote:
> If user could not see any message from a pool which he/she leave, even
> his/her message, What will happen?
> In a company, If some one leave a team/project/department, he/she may be
> could not read any document even he/she write.
>
> The messages are also some resource for a team/project/department, I think
> it's fine that do not allow users can not read any messages in the pool.
>
> Think about jira, if you create a issue(task, defects) and the permission
> said only team members.
> And if you leave the team, you can not read the issue anymore.
>
>
>
> On Thu, Oct 1, 2009 at 12:51 PM, Richard Hirsch <hirsch.dick@gmail.com>wrote:
>
>> Regarding the first part (deleting users from a pool) - here are my ideas
>> * We have no idea whether he has viewed the messages or not.
>> * Of course, he should be able to continue see his own messages even
>> if they were sent to a pool to which he no longer belongs.
>> * The user's messages remain in the pool whether or not the user is in the
>> pool.
>> * Since the user can no longer view the pool, he can only view his own
>> messages but not those of other users.
>> * Question: Should we delete all old messages from the pool to which
>> the user was a member or should we just prevent new messages from the
>> now-forbidden pool going to the user. I prefer the second choice.
>>
>> Thoughts?
>>
>> To the second point regarding the deletion of pools. I think this
>> needs more thought. We can't / shouldn't delete messages from closed
>> pools. This would be a performance and programming nightmare.
>>
>> D.
>>
>> On Thu, Oct 1, 2009 at 5:23 AM, Xuefeng Wu <benewu@gmail.com> wrote:
>> > There're two features:1. delete users from pool;
>> > 2. delete pool.
>> >
>> > There're some argue and my opinion:
>> > *when delete users from pool.*
>> > We could withdraw all messages from the user, whatever read or unread.
>> >
>> > *when delete pool. ESME-68*
>> > withdraw all messages
>> > can create new pool which have the same name as deleted
>> >
>> >
>> >
>> > On Wed, Sep 30, 2009 at 3:59 PM, Vassil Dichev <vdichev@apache.org>
>> wrote:
>> >
>> >> > Should we allow for a user to be deleted from an access pool?
>> >> >
>> >> > If yes what happens? Does he no longer have access to the messages in
>> >> > the pool - irregardless of whether he wrote them or not?
>> >>
>> >> It should be possible to delete a user, yes. I think it has been
>> >> discussed or specified in the requirements pdf that once a message is
>> >> in the user's mailbox, it stays there, so that's how it works now. At
>> >> any rate, deleting a message from the mailbox, which the user may have
>> >> already seen doesn't offer any more security. A user also doesn't see
>> >> messages in his/her mailbox, which were sent before he was added to
>> >> the pool.
>> >>
>> >> The interesting part is what happens if a pool has been removed and
>> >> whether it should be possible at all. This could pose a security
>> >> problem if an impostor creates a pool with the same name (similar to
>> >> what might happen with a deleted user account)
>> >>
>> >
>> >
>> >
>> > --
>> > Global R&D Center,Shanghai China,Carestream Health, Inc.
>> > Tel:(86-21)3852 6101
>> >
>>
>
>
>
> --
> Global R&D Center,Shanghai China,Carestream Health, Inc.
> Tel:(86-21)3852 6101
>