[Digikam-users] Digikam slow

[Dotan Cohen]

On 08/12/2007, Andreas Weigl <kde at silicoids-world.de> wrote:
> Hi
>
> Am Friday 07 December 2007 schrieb Dotan Cohen:
> > While googling, I came across this:
> > http://rudd-o.com/archives/2007/10/02/tales-from-responsivenessland-why-lin
> >ux-feels-slow-and-how-to-fix-that/2/ Might that be relevant? Should I try
> > writing vm.swappiness=1 to
> > /etc/sysctl.conf? What side effect might that have?
>
> No. A bigger filesystem cache would only help if you had a lot of IO ( => high
> system or wait io value in vmstat). The problem seems to be the "application
> cache" of the thumbnails.
>
> Did you check if you actually have files in .thumbnails?

Yes, opening an album in Digikam makes the thumbnails appear in ~/.thumbnails.

> I think you could have one of the following problems:
>
> 1. Thumbnail cache too small (don't know how to increase it further)

It's 100 MB, as per Kcontrol. Although, I think that is too small for
over 13,000 photos. 13000 * 100 KB = 1.3 GB.

> 2. The thumbnails can not be written to the .thumbnail directory so the are
> generated each time (permission problem)

Checked, they are most certainly written.

> 3. Whenever it is checked if your image has been changed since the thumbnail
> was generated the result is that the image is newer. So the thumbnail has to
> be regenerated. I don't know what the criterias are (timestamp or something
> else). Did you check the creation time of your original images (ls -l). Maybe
> they are in the future.

Interesting idea, but alas, this is not the problem.

Another thing that I have noticed:
Digikam does not make thumbnails until the thumbnail in question is
meant to be displayed on the screen. So if I want the thumbnails of
all the photos in an album, I must pan slowly down, so that each one
will have a chance to be created. After that, I can pan up and down
quickly with almost no lag in the thumbnail's display. However, if I
switch to another album and then back, once again I have a delay in
the display of the thumbnails. It is not so long as it would take to
create the thumbnails again, however it is extremely sluggish.

We are considering replacing this aging computer. I will start a new
thread asking about processor/memory recommendations for a machine
that's main purpose will be to run digikam (as this one is).

Dotan Cohen

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