Subject: Issue: ALLPROP_AND_COMPUTED

From: "Jim Whitehead" <[email-masked]>
Date: Wed, 25 Apr 2001 11:19:54 -0700

This issue is currently stated as:

If a server has some computed properties which are expensive to compute,
then PROPFIND allprop, especially PROPFIND allprop with Depth infinity can
be an expensive operation.  There should be an implementation note added to
the document noting this problem.  Suggestion that servers might want to be
conservative in their implementation of such compute expensive properties.
Clients should only perform PROPFIND allprop when necessary, not by default.

It was raised by Ken Coar at the Advanced Collections breakout at the
Orlando IETF meeting.

But, since that time there has been a substantive discussion of this issue,
begun by Lisa Dusseault, starting at:

http://lists.w3.org/Archives/Public/w3c-dist-auth/2000OctDec/0034.html

My understanding of the rough sentiment of the working group is:

1) PROPFIND allprop requests with Depth infinity should be deprecated. That
is, PROPFIND allprop with Depth infinity will remain in the WebDAV
Distributed Authoring Protocol, but there will be a requirements added that
new clients MUST NOT use this capability.  When existing clients are
revised, they SHOULD be rewritten to avoid using PROPFIND allprop Depth
infinity requests. This will only apply to PROPFIND allprop with Depth
infinity -- PROPFIND allprop for Depth 0 and 1 will still be OK.

2) The default behavior of PROPFIND will be changed so it is Depth 0, not
Depth infinity.

- Jim

---

From: Greg Stein <[email-masked]>
Date: Thu, 26 Apr 2001 09:24:37 -0700

On Wed, Apr 25, 2001 at 11:19:54AM -0700, Jim Whitehead wrote:
>...

Toss the timing stuff. The revised text should simply state that clients
MUST NOT use the capability. Some existing clients will "not conform" for a
bit, but that is not our problem, and it probably won't be an issue anyways.

> 2) The default behavior of PROPFIND will be changed so it is Depth 0, not

I agree with this one, but it could be a troublesome change. mod_dav
normally disallows Depth:infinity PROPFINDs (unless the server is confiured
to allow them), so maybe clients are used to sending a Depth:0 or 1. Hard to
say. The point is that a client that doesn't send a depth header, and
expects a depth of infinity is going to be very surprised by a Depth:0
response.

Cheers,
-g

-- 
Greg Stein, http://www.lyra.org/