Horde speed (was: Sluggish Horde Webinterface)

[Gunnar Wrobel]

Hi Saim,

Saim Kim <s.kim at hia.rwth-aachen.de> writes:

> Hello,
>
> is it normal for the Horde Webclient calendar to be sluggish? I'm using 
> the Kolab Server 2.2 RC 2 with the Horde option. I found an entry in the 
> Kolabwikki about the "c-client patch". Is this patch already included in 
> rc2?

the answer to that is a little bit more involved and I'm temped to
give an overview on Horde speed issues in general.

All Horde/Kolab speed issues are basically focussed around the IMAP
connection. About two years ago Horde was only able to contact the
Kolab IMAP server, to list all folders of the user, and to load as
well as parse the messages in a folder desired by the user.

This happened on EVERY page view. If you clicked on a calendar link in
Horde you'd get a massive amount of IMAP calls and once you more than
a few dozen items in a Kolab folder (e.g. events or contacts) you'd
notice a very serious delay.

There are three levels on which this can be improved:

  1) Speed of the IMAP connection in general

  2) Caching of the items in a folder so that you don't have to
     reparse all contacts, events, etc. on every page view.

  3) Caching of the IMAP folders of a user so that Horde does not have
     to query IMAP for a list of mailboxes on every page view.

You mentioned the 'c-client patch'. This is level 1). And yes, it is
included in the recent Kolab Server 2.2 release candidates. It is in
fact a very central Kolab specific patch and has already been used in
2.1. The patch speeds up the IMAP connection as it provides the
internal PHP IMAP implementation with functions that are essential for
the Kolab Server. If PHP has not been patched with this the only
alternative is to use the PEAR-Net_IMAP package which provides an
alternative IMAP implementation but is significantly slower as it is
purely implemented in PHP.

So on level 1) the Kolab Server should be fine. At least the OpenPKG
as it is usually harder to get PHP patched on the other
distributions. I know that Gentoo supports the Kolab patch by now but
Debian probably does not.

Level 2), the caching of folder items such as events and contacts has
been implemented in PHP by Thomas Jarosch and we worked together on
getting this into Horde. This has been available within Horde for
about a year now. BUT I did not build the Kolab server packages
correctly and so anything up to Kolab Server 2.2 RC2 should be unable
to actually write the cache. This should be fixed with RC3. So I
expect Horde to be sluggish in case you have many items in your
folders as they probably get reparsed on every page view.

Level 3), the caching of folder lists went into Horde last week and is
not yet finished. Currently all Horde installations still elicit IMAP
calls on EVERY page view. Which means you will experience lags
especially if your users have many folders. The coding I did last week
has the capability to reduce the IMAP calls on a page view to
zero. Removing the need for calls that open network connections brings
a significant speed gain. But I would not expect this to hit the Kolab
server on OpenPKG before the end of this year.

Once all that is working in a stable fashion there might still be
another round of speed optimizations by doing code profiling. That
tends to help a lot with PHP too. But that has nothing to do with IMAP
and is currently just a mental note in my head.

To summarize the current status of the Horde web client speed when
using it with Kolab: We are halfway there but you can still expect
some unnerving delays.

Cheers,

Gunnar

>
> Best regards,
> Saim
>
>
> -- 
> --------------------------------------------------------------------------
> Dipl.-Ing. Saim Kim
> Lehrstuhl fuer Medizinische Informationstechnik
> Helmholtz-Institut fuer Biomedizinische Technik
> RWTH Aachen
> Pauwelsstr. 20, D-52074 Aachen
> ---
> Web:   http://www.medit.hia.rwth-aachen.de/
> Tel:   +49-(0)241-80 23218
> Fax:   +49-(0)241-80 82442
> email: s.kim at hia.rwth-aachen.de
> -------------------------------------------------------------------------- 
>
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