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From Nehal Mehta <>
Subject Re: Row level visibility
Date Mon, 27 Jan 2014 04:44:17 GMT
Thanks for all information.

But VisibilityConstraint disallows user writing data that it cannot see.
Correct me if I am wrong.

In our use case as mentioned above, we want one set of user who can still
read/access that data but not update it. So each cell we need to store read
as well as write visibility. We cannot have one single environment based
constraint.  Do you people know if anyone else in community requires such
visibility granularity?


On Sun, Jan 26, 2014 at 11:29 PM, Josh Elser <> wrote:

> It sounds like you might be able to use something like the Constraint[1]
> interface, notably the VisibilityConstraint[2] implementation, to get what
> you want already.
> That would disallow any updates with a visibility that the user writing
> the data cannot see. You could probably come up with a way to structure
> your visibilities to work within that functionality.
> [1]
> core/constraints/Constraint.html
> [2]
> core/security/VisibilityConstraint.html
> On 1/26/14, 10:55 PM, Nehal Mehta wrote:
>> Thanks John. I do understand we can define those permissions at table
>> level
>> or user level. Our application needs it to be defined at row/cell level.
>> But here what we are trying to achieve is to have them at row level. So
>> suppose a user of group inserts data, it can be updated by same group but
>> not another group. Multiple other groups can still read that data.  So
>> basically we would have to define it at row level. In that way, lot of
>> applications can be developed on top of accumulo without worrying about
>> read-update validations at application.
>> Basically we want row level information to be created and updated by one
>> set of group but can be read by multiple groups. Multiple groups write
>> data
>> to that same table. Do you think accumulo wants to support that in future?
>> Instead of having just cell visibility we have two set of visibility for
>> each cell: 1) Read Visibility 2) Write (Update) Visibility.
>> Thanks,
>> Nehal
>> On Sun, Jan 26, 2014 at 9:59 PM, John Vines <> wrote:
>>  I think there may be two things which would satisfy your request.
>>> 1. For tables, there are both READ and WRITE ACLs used to determine read
>>> and write access. If a user does not have read permission, they will be
>>> unable to get any data (with READ permissions, it will then fall back to
>>> the authorizations). Similarly, if a user lacks the WRITE permission,
>>> they
>>> can't do any inserts.
>>> 2. For a user with WRITE permission, there is a constraint which can be
>>> applied to a table which only allows them to write data with a label they
>>> have permission to read. This would effectively allow cell level write
>>> control, in addition to read control.
>>> Hopefully that provides some insight.
>>> On Sun, Jan 26, 2014 at 7:51 PM, Nehal Mehta <> wrote:
>>>  Hi,
>>>> Is accumulo considering row level visibility for read and write
>>> (updates).
>>>> Basically in one of our application we want user to insert rows with
>>>> different visibility options for updating that row vs reading that row.
>>> We
>>>> want one role to be restricted to just read that row but another special
>>>> role to update as well as read that row.
>>>> By having read and update visibility accumulo can expose more rows as
>>> there
>>>> is no fear of them being updated.
>>>> I am relatively new user of accumulo and if this is already discussed in
>>>> past, can anyone guide me to that discussion?
>>>> Thanks,
>>>> Nehal

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