MBOX-Line: From dave at cridland.net  Mon Aug 30 01:22:49 2010
To: imap-protocol@u.washington.edu
From: Dave Cridland <dave@cridland.net>
Date: Fri Jun  8 12:34:45 2018
Subject: [Imap-protocol] "Multiple Commands in Progress" real life
	support and ambiguity questions
In-Reply-To: <alpine.OSX.2.00.1008291038500.370@hsinghsing.panda.com>
References: <4C7A2AB6.6070405@lists.grepular.com>
	<alpine.OSX.2.00.1008291038500.370@hsinghsing.panda.com>
Message-ID: <2721.1283156569.612563@puncture>

On Sun Aug 29 19:31:58 2010, Mark Crispin wrote:
> Few, if any, IMAP servers will execute commands out of order.
> 
> 
I don't know of any for certain, but if anyone's implementation does,  
it'll be Arnt/AMS's.

> As a server implementor, you can disregard section 5.5 entirely,  
> with the
> exception that you MUST NOT clear the command input buffer after  
> reading a
> command (because there may be a pipelined command following the  
> current
> command).  Section 5.5 should be considered to be solely  
> implementation
> advice for clients that wish to pipeline.

FWIW, my client can cope with out-of-order execution. My ACAP server  
does ACAP commands out of order (where the protocol support is  
simpler).

The only case where it would be useful is SEARCH - searches can take  
time on larger mailboxes, and being able to execute a simple FETCH of  
a bodypart during the search would be beneficial. To allow for this,  
Polymer assumes that searches as a whole are executed concurrently,  
in the absence of ESEARCH - ESEARCH includes a tag in the results,  
effectively mimicking ACAP's tagged intermediate responses. Polymer  
uses SEARCH quite extensively, especially if filtered views are in  
heavy use, and one of the reasons I never put in multiple views of a  
single mailbox is that the SEARCHes in one view would simply stall  
the other view.

(I imagine this also applies to THREAD and SORT).

As Mark says, in most implementations the bottleneck would be such  
that servers are unlikely to be able to do much, but I suspect that  
there are some cases where it would be possible, in some servers.

Dave.
-- 
Dave Cridland - mailto:dave@cridland.net - xmpp:dwd@dave.cridland.net
  - acap://acap.dave.cridland.net/byowner/user/dwd/bookmarks/
  - http://dave.cridland.net/
Infotrope Polymer - ACAP, IMAP, ESMTP, and Lemonade

