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Re: [WebStorage] Concerns on spec section 'Processing Model'

From: Nikunj R. Mehta <nikunj.mehta@oracle.com>
Date: Fri, 24 Jul 2009 16:30:21 -0700
Cc: Ian Hickson <ian@hixie.ch>, public-webapps WG <public-webapps@w3.org>, Laxmi Narsimha Rao Oruganti <Laxmi.Oruganti@microsoft.com>
Message-Id: <81105401-1E82-43C2-9A59-008F14BB3A16@oracle.com>
To: Aaron Boodman <aa@google.com>

On Jul 24, 2009, at 3:57 PM, Aaron Boodman wrote:

>>> I do not agree that database-level locking is a big problem for web
>>> applications.
>>
>> Our problem is not with databases doing database-level locking. Our  
>> problem
>> is that such behavior is a MUST.
>
> I think it is very desirable for it to appear to the developer that
> writes to the local datastore are atomic. Lots of complexity falls out
> if this is not true.

It is implicit that transactions give atomicity (that's what A in ACID  
stands for). It would be mischaracterizing this discussion to say that  
we are arguing about atomicity. We are, however, talking about  
isolation (the I in ACID), or more precisely the degree of isolation.

> In some models (non-SQL) it may be easier to
> arrange a large update in the application layer and commit it all at
> once. In SQL, this is less true so it is important to provide API that
> makes conflicts impossible while a multi-step update is in progress.

This problem exists in the WebStorage model [1]. More specifically,  
there is no way to perform multiple updates atomically in it.

The proposal that I have sketched about B-trees [2] does not have this  
problem since it is possible to work with transactions to get the  
atomicity as well as a desired isolation level. I take it that there  
are no issues with that proposal since I have not heard anyone say so.

>
> Perhaps your real issue is that the current API does not work well for
> non SQL data stores.

Not at all! It would be disingenuous to find an ulterior motive in my  
arguments.

Nikunj
http://o-micron.blogspot.com

[1] http://dev.w3.org/html5/webstorage/
[2] http://www.w3.org/mid/F480F60A-5DAE-4B73-922A-93ED401CF32C@oracle.com
Received on Friday, 24 July 2009 23:32:52 GMT

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