[imp] disallow Dynamic View

[Brendan Oakley]

Hi Ralf,

On Thu, Jan 17, 2013 at 2:19 PM, Ralf Lang wrote:
>
> Mind the * $conf[cache][use_memorycache] setting.
> You can configure a first-level in-memory cache (APC, memcached) which falls
> through to the disk or sql based
> $conf[cache][driver] when it doesn't hit.

Oh, I understand now. Thanks for explaining that.

I have now done some more testing, in Basic mode. I tried with and
without the local file cache, and surprisingly the performance is
exactly the same. I tried switching to SQL-based cache, and the
application crashes, with "Lock wait timeout exceeded." This was with
only one web server. At this point my inclination is to just leave it
off for now.

> Still, I wonder why dynamic mode stresses your imap server more than
> classic.

My guess is that the dynamic mode is simply designed for IMAP servers
with faster responses. Ours can get pretty slow under load. It
appeared to me as if it was queuing up commands, and if the one took
too long, IMP would time out and raise an error talking to the server,
and then all the subsequent commands that had been waiting their turn
would throw an error, so the screen peppers itself with red error
messages. The preview pane was very aggressive in this respect. That's
not behavior we can have happening. It doesn't mean anything is wrong
with IMP's dynamic mode per say, it just isn't going to work with the
latency in our environment. Basic mode still feels slow at times, but
it stays clean and predictable, and the IMAP server only gets hit when
a user deliberately clicks a link.

I'm not terribly concerned about it because of course we plan to
change the storage backend once it is decoupled from the other
components. Integrating Horde into our site is part of this process.
After that the performance tuning will take higher priority.

I got the preauth hook working now BTW. It was actually simple. Just
check for $browser->isMobile() in the case of 'auto'. It's as good a
place as any to add the hook, because the mode is set at
authentication.

Thanks
Brendan