Calendar is very slow with CalDAV (was: No Lightning for Aurora?)

On Di. 26.06.2012 18:59, Stefan Sitter wrote:
> Peter Lairo wrote:
>>> The latest Thunderbird daily with the latest Lightning nightly
>>> builds are completely unresponsive.
>>>
>>> I have Windows 7, a quad-core CPU, and 4 GB RAM. For the past 2
>>> hours (I've been waiting to see if it will get better), Thunderbird
>>> has been "Not Responding" and is constantly using 25% CPU and 675
>>> MB RAM.
>>
>> Update: After *four hours* Thunderbird and Lightning became
>> responsive again. Well, "responsive" is a bit of an exaggeration.
>> Lightning still stalls for about 10 seconds whenever I page to
>> another week or month, and the calendars take a "while" to display.
>> Also, Thunderbird will stall for a few seconds (e.g., the text I'm
>> typing will not appear, and then pop-in after a few seconds). It's a
>> very frustrating experience.
>>
>> Does anyone know if there's a bug on this performance issue yet?
>
> I use Earlybird for daily use and so far I have not experienced
> performance problems. But I use only ics based calendars and therefore
> can't comment on CalDAV.

That surprises me (I'm assuming your a developer of Lightning). I 
thought ICS was to CalDAV as POP is to IMAP. I thought ICS was less 
"awesome" than CalDAV. Why would a developer not use the most awesome 
tech available? And even is the developer used ICS/POP, wouldn't it be 
beneficial to their product to make sure that the awesome tech worked well?

> But as written before the CalDAV provider has
> changed a lot in Lightning 1.7 and 1.8 therefore it might be possible
> that something regressed.

I doubt that. The slowness with CalDav has existed in Lightning forever.

> Regarding performance you should check the find events filter settings,
> the task tab filter settings and the today pane task list filter
> settings. If one of them is set to "All" Lightning will download the
> entire data of all your calendars during startup. Depending on calendar
> size this might take a while.

During *every* startup? If that is the case, then Lightning is in need 
of major work to make CalDAV work better "out of the box".

> You could test if enabling offline cache improves performance.

I'm afraid to do this because it's very important data and I don't trust 
the offline cache with CalDAV because the deveopers don't seem to have 
focused on CalDAV enough to prevent at least the serious dataloss 
possibilities (not eating your own dogfood).

> You could test if disabling or enabling the SPDY protocol that is used
> with Google servers has any impact on the performance.

How would I do that? about:config? Which setting(s)?

> You could test if the number of calendars has any impact on the
> performance, i.e. calendar 1 alone, calendar 2 alone, and 1+2 switched
> on at the same time.

It's slow with even one large calendar. decreasing the number of 
calendars merely makes it slightly less "too slow".

Thanks for your thoughtful reply.

Peter Lairo