[sugar] Journal view "flips" topmost entries

[Morgan Collett]

On Tue, Aug 12, 2008 at 00:12, Eben Eliason <eben.eliason at gmail.com> wrote:
> On Mon, Aug 11, 2008 at 4:51 PM, Mikus Grinbergs <mikus at bga.com> wrote:
>> My guess is that "flipping" of the topmost entries in Journal has to
>> do with "scheduling" rather than with "communications".  Though in
>
> I'm sure that what you are seeing results from the fact that the
> Journal defers updating itself until its window is shown, to prevent
> needless updates from occurring in the background and taking extra CPU
> cycles.  It's unfortunate that the single update that occurs when the
> Journal is focused has so much latency...this should really be
> happening so quickly as to be unnoticeable.  There are a lot of pieces
> of the Journal that could use some optimiation, among them the actual
> rendering of the entries themselves when a change occurs (try
> starring/unstarring and see how long it takes it to redraw to reflect
> the change! (http://dev.laptop.org/ticket/7151)).
>
> That said, the circumstance you describe is truly not good; in fact,
> without a confirmation alert upon deletion, this could might even be
> considered a blocker.  Could you open a ticket describing the problem,
> and note that adding a confirmation might be a valid short term
> workaround to prevent accidental deletions? (Actually, just found
> this: http://dev.laptop.org/ticket/3778.  Could you update this ticket
> with your experience and perhaps add a blocks?:8.2.0 tag so it's
> considered?)
>
> Clearly we need to this and also plenty of optimization in the future.
>
> - Eben
>
> PS.  If you truly are seeing the flip apart from the first time the
> Journal is shown, there is something else amiss.  Please keep an eye
> out and confirm one way or the other if you actually experience such
> behavior.  Thanks!

I see the flipping - it's easy to reproduce. With two open terminals
(named differently) if I just hit alt-tab from the Journal, to the
first terminal, and without releasing alt I hit tab again to the
second terminal, and then tab again to the Journal, I get a momentary
flip.

What is happening, as far as I can tell, is that when you tab *away*
from the first terminal it updates the datastore (of which the Journal
is a view), so it is now the most recent entry. Then when you tab away
from the second terminal - back to Journal - it updates the datastore
too. When you see the Journal it updates itself, and Terminal 1 first
jumps to the top, then Terminal 2.

For me it happens quickly - less than half a second or so. If the XO
is under some load (other running processes?) then it might take
longer - or perhaps if there are many journal entries?

Regards
Morgan