[imp] Why would dimp be slower to generate message list than imp?

[Michael M Slusarz]

Quoting Gimili <gimili17 at gmail.com>:

> On Thu, Jul 10, 2008 at 12:50 PM, Michael M Slusarz <slusarz at horde.org>
> wrote:
>
>> Quoting gimili <gimili17 at gmail.com>:
>>
>>  Why would dimp be *significantly* slower to generate message list than imp
>>> on a large mailbox?
>>>
>>
>> DIMP isn't slower per se - both DIMP and IMP use the exact same functions
>> to generate the message lists.  However, DIMP processes a larger chunk of
>> messages at a time than IMP does.  In a typical mailbox, IMP displays by
>> default 20 messages per page while DIMP downloads, by default, 7 times the
>> size of the current viewport (if the current viewport is 20 messages, DIMP
>> downloads the message information for 140 messages).  The tradeoff is
>> slightly slower initial display in DIMP for subsequent instantaneous
>> scrolling through the mailbox (at least the portion that is loaded) while in
>> IMP, you would have to wait for each subsequent page to load which takes
>> much longer and also hammers the server (a single request for message info
>> 140 messages is more than 700% more efficient than 7 requests for 20
>> messages each).
>>
>
> Thanks kindly for explanation.  This was not "slightly slower".  It was so
> slow I could hardly use it.  I went to imp's options and changed my viewport
> from 200 messages to 20 and now dimp works.  With 200 and a large inbox dimp
> does not work very well at all.  I am not sure if the total number of
> messages makes a difference as everything seemed slow with the display set
> to 200 messages per page.

This makes absolutely no sense.  The max_msgs preference is used only  
in the IMP_Mailbox::buildMailboxPage() function, and that function is  
never called from dimp.  Changing that preference will cause no  
difference in performance in dimp.

michael

-- 
___________________________________
Michael Slusarz [slusarz at horde.org]