Subject: Standardizing Batch methods?

From: <[email-masked]>
Date: Fri, 5 Oct 2007 16:15:52 +0200

Hello,

are there any plans for standardizing Batch methods in WebDAV? Is there
a spec that could be discussed or are there real alternatives to
transactions in WebDAV?
I searched in the WebDAV mailing list archive, but the last posts
according to that issue are quite old. 

Cheers,
Markus
-- 
Markus Litz
DLR (German Aerospace Center), 
Simulation and Software Technology
Linder Hoehe, 51147 Cologne, Germany
voice: +49 2203 601 2018 	fax: +49 2203 601 3070
eMail: Markus.Litz at dlr.de      http://www.dlr.de/sc

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From: Julian Reschke <[email-masked]>
Date: Sat, 06 Oct 2007 12:08:10 +0200

> a spec that could be discussed or are there real alternatives to

I'm not aware of any plans. Things I *am* aware of are:

- two documents for which documentation was requested (BIND, SEARCH) -- 
waiting for the IESG

- a proposal to work on an equivalent of CaldDAV for vCard. Potentially 
a WG will be formed for that, and there was some discussion about 
starting some separate documents simplifying this in the WebDAV stack 
(such as defining a request body for MKCOL, or extrating stuff like 
REPORT from RFC3253).

- maintenance of existing specs (RFC3253bis, RFC3744bis, RFC4918bis...).

> according to that issue are quite old. 

I would guess we'd need to come up with a problem statement first.

There are both batch calls and transaction support in Microsoft 
exchange, and as far as I recall these have the following issues:

Batch: underspecification, not clear whether it's good for retrieval 
because it bypasses caches.

Transactions: breaks GET, because specifying the transaction id as a 
request header essentially makes all requests content-negotiated.

So... what's the problem you're looking to solve?

Best regards, Julian

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From: Tim Olsen <[email-masked]>
Date: Sat, 6 Oct 2007 09:01:13 -0400

> a spec that could be discussed or are there real alternatives to

DeltaV activities may be able to do what you're looking for.

-Tim

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From: <[email-masked]>
Date: Sun, 7 Oct 2007 21:46:30 +0200

We develop a WebDAV client specialized for organizing scientific data and one of its main requirements is absolute data integrity. There are many situations on which one user action results in several webdav-request. This leads to two serious disadvantages. First, if a user action leads to 50 or 100 webdav request, depending on the network bandwidth and server performance, this could be really slow. And secondly if the client crashes in the middle of a difficult job, this could result in inconsistent data.
Some time ago, there was a discussion about microsofts batch methods and transactions, which deals about exact the same problems we facing here. So, I'm interested if in the meantime one of this solutions had lead to a draft status or if this issue had been discarded. Maybe our organization could help working to accelerate the progress of writing a draft.

-Markus

________________________________

Von: Tim Olsen [mailto:[email-masked]]
Gesendet: Sa 06.10.2007 15:01
An: Litz, Markus
Cc: [email-masked]
Betreff: Re: Standardizing Batch methods?

-Tim

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From: Werner Donné <[email-masked]>
Date: Mon, 08 Oct 2007 08:42:51 +0200

At the moment it is not possible for a WebDAV server to participate
in a distributed transaction. Applications may wish to store documents
in the course of a transaction and be sure that this is rolled back
in case of a failure. I'm therefore in favour of introducing an XA
interface in WebDAV.

There is also a case for having explicit transaction demarcation
methods. For example, clients can benefit from executing a simple
sequence such as check-out/update/check-in in the context of a transation.

Regards,

Werner.

-- 
Werner Donné  --  Re
Engelbeekstraat 8
B-3300 Tienen
tel: (+32) 486 425803	e-mail: [email-masked]

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From: Julian Reschke <[email-masked]>
Date: Mon, 08 Oct 2007 10:16:26 +0200

> Some time ago, there was a discussion about microsofts batch methods and transactions, which deals about exact the same problems we facing here. So, I'm interested if in the meantime one of this so…

Markus,

the main issue here is that it's totally non-trivial to define batch and 
transactions methods over HTTP.

- for batch: things that bypass caches and pipelining may be slower in 
practice.

- for transactions: I'm only aware of one implementation (Microsoft's), 
and that one breaks HTTP semantics.

So, if you want to get somewhere somebody will have to make a proposal 
and start work implementing it inside a server, proving that it indeed 
works and performs well.

Best regards, Julian

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From: <[email-masked]>
Date: Mon, 8 Oct 2007 19:02:20 +0200

Hi Julian,

so this is indeed a unsolved problem. I was wondering if someone already started with writing a proposal for either batch calls or transactions. Was there a discussion on which a preference became clear? 
The best may be if I start with reading the microsoft batch & transaction definitions, and than we consider to start working on a draft.

Ideas?
Markus

-----Ursprüngliche Nachricht-----
Von: Julian Reschke [mailto:[email-masked]]
Gesendet: Mo 08.10.2007 10:16
An: Litz, Markus
Cc: [email-masked]; [email-masked]
Betreff: Re: AW: Standardizing Batch methods?

Markus,

Best regards, Julian

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From: Julian Reschke <[email-masked]>
Date: Mon, 08 Oct 2007 19:11:39 +0200

> The best may be if I start with reading the microsoft batch & transaction definitions, and than we consider to start working on a draft.

I would say working on a draft can be useful, but what's even more 
important is to find people willing to implement it. Just writing a 
draft is unlikely to make implementations happen (even RFC4918 IMHO so 
far has a *single* implementation...).

So I'd urge you to first understand what the problems with the Microsoft 
implementations are, and then to check whether the advanced features 
defined in RFC3253 do not already do what you're looking for (at least 
with respect to transactions).

Best regards, Julian

---

From: "Joe Feise" <[email-masked]>
Date: Mon, 8 Oct 2007 10:52:22 -0700 (PDT)

How about starting with the workspace and activity concepts in DeltaV?

-Joe

On Mon, October 8, 2007 10:02, [email-masked] wrote:
>
> Hi Julian,
>
>
>
> so this is indeed a unsolved problem. I was wondering if someone already
> started with writing a proposal for either batch calls or transactions.
> Was there a discussion on which a preference became clear?
> The best may be if I start with reading the microsoft batch & transaction
> definitions, and than we consider to start working on a draft.
>
> Ideas?
> Markus
>
>
>
>> We develop a WebDAV client specialized for organizing scientific data
>> and one of its main requirements is absolute data integrity. There are
>> many situations on which one user action results in several
>> webdav-request. This leads to two serious disadvantages. First, if a
>> user action leads to 50 or 100 webdav request, depending on the network
>> bandwidth and server performance, this could be really slow. And
>> secondly if the client crashes in the middle of a difficult job, this
>> could result in inconsistent data.
>> Some time ago, there was a discussion about microsofts batch methods and
>> transactions, which deals about exact the same problems we facing here.
>> So, I'm interested if in the meantime one of this solutions had lead to
>> a draft status or if this issue had been discarded. Maybe our
>> organization could help working to accelerate the progress of writing a
>> draft.
>
> Markus,
>

---

From: "Markus Litz" <[email-masked]>
Date: Tue, 9 Oct 2007 21:24:01 +0200

Julian, Joe, Werner,

thank for your hints. I will check advanced versioning, maybe it
complies with our requirements. If it goes not far enough, we may
consider to work on a draft either on transactions or batch methods.
Then we plan anyway to do a reference implementation to stimulate
others to follow that path, but I'm pessimistic that _one_
implementation could do that...

Anyway, I'll inform this list on out next steps, eventually others
come to the same situation and need some inspiration.

So long
Markus