How tracker works
 

For those that don't know, tracker is the utility that watches for new media and makes thumbnails of new images on your N900. It has been widely cursed and hated for its poor behavior and can cause sluggish response time while doing its thing -- which it tends to do right when you want to use your N900, like when taking a bunch of photos.

There is a configuration file for tracker in /home/user/.config/tracker/ called tracker.cfg. By default it has quite a few comments that can be helpful in deciphering the settings, but i find i'm still not really sure what the default behavior of tracker is. There's also an app called tracker-cfg that lets you edit these settings with a GUI.

There are three categories you can put individual folders into that determine how tracker treats them (please correct any errors here) (Edit: see this later post for links to more complete descriptions):

• crawl - scan the folder only when it is first mounted and index any relevant files
• watch - every time the folder contents change, reindex it
• don't watch - don't ever index the directory

The way these are specified can be a bit confusing, because for example you specify a root folder to be watched (meaning tracker will automatically watch all its subfolders). It's not clear if it works the same way for the other two lists.

I'd appreciate a description of the behavior if anyone understands it. In particular, i'm wondering what the default rule is for folders not specifically included in any lists. and whether the "do not watch" list is for directory roots or just individual directories.

The current configuration on my N900 is supposed to be not watching a specific directory of web images, but i keep seeing them show up in the images listing after rebuilding the database. (tracker-processes -r)

Some of the other options are a bit confusing as well. Is there better documentation for this somewhere?

Thanks in advance for whatever insights you might have on the inner workings of tracker. I'd like to tame it! :eek:

Re: How tracker works
 

You should check out the program called tracker-config. It not only lets you set all these parameters manually (thus making tracker actually, y'know, bearable), but it also helps on understanding how it works.

Re: How tracker works
 

Tracker is all open source, so you can check out exactly what's being done from the code (the manual pages are the best place to start). According to the trackerd manual page, all three groups automatically include all (non-hidden) subdirectories.

Re: How tracker works
 

shouldnt it be so, that it indexes pictures when you open the photo-viewer or movie/song-files when you start the mediaplayer?

Re: How tracker works
 

mmmmm
I would like it to index the new pictures/videos AFTER I've shot them, after LEAVING the application that made them. Not during...

In general, while I'm doing the creation, I would want as little other system activity as possible. Real multi-tasking on a limited resource device only goes that far ... Ask Apple and Google.

So while doing time critical stuff, I ideally want all non-critical stuff frozen.
That would help the stuttering while filming.

But that's asking too much I guess ...

Re: How tracker works
 

I think that it should be possible to send some kind of suspend/pause command for tracker. This could be trickered by for example when the lens cover is opened (maybe this could be integrated to Lens cover reminder application?). I assume that Camera app is closed source so this functionality probably can not be integrated to camera itself (?).

Are there other non-critical processes than Tracker running that are so resource consuming that they should be stopped too while filming?

(Disclaimer: I am not a developer so this is mostly something that I have been thinking and don't have a slightest idea if this makes really any sense at all... :o )

Re: How tracker works
 

Something like this:
Pictures get indexed after camera app is closed, the same with videos.
Inside media player there should be a button to chose "Auto Indexing" (index always one) or "Manual Indexing".
When Manual Indexing is chosen you get another button that says "Scan for new media", that triggers the Tracker to index new music and videos. It works that way on Symbian S60 3rd if I dont remember wrong.

Re: How tracker works
 

Thanks. I actually mentioned it by name in my post. ;)

It is handy but i uninstalled it when i realized that the default configuration file is actually commented clearly and tracker-cfg is just a wrapper for a single user config file. It is nice to have the options to rebuild database &tc right in the app, but that's also easy to do manually.

Thanks Rob1n. I hear so many complaints about tracker i just assumed it was one of the closed bits of maemo. It does seem unduly hard to set it up to behave as desired, so i'll check out the manual.

One thing you can change that will have very apparent results is increase the throttle. If it's around 10 the slowdown will be much less noticeable.

Re: How tracker works
 

If I'm filming I'm not interested in getting new email notices ... or IM messages. I want a good steady shot, no dropped frames, maybe even some help from the CPU in non-favorable light conditions.

If the hardware/software implementation is not powerful enough to do all at once, then I think things should be pragmatic.
I do think the Maemo ecosystem is too much desktop Linux driven, actually ahead of it's time, designed for devices with ample resources, allowing the walhalla of real-time multitasking at the expense of user experience and performance of the frontend tasks.

Lets hope Meego has better provisions for preserving User Experience and performance. But honestly, I think better HW is the only thing to keep all running as envisioned during design.

Re: How tracker works
 

Here's the man page for the tracker configuration file: http://linux.die.net/man/5/tracker.cfg

Here's the project page: http://projects.gnome.org/tracker

Now that i've read up on it, i'm more curious than ever at some of the options. AFAIK, there's no built-in global search capability in maemo, so all of the file content options in tracker configuration seem pointless, yet not disabled in the default tracker configuration. Does anyone know what use maemo makes of tracker's content indexing besides the very basic task of thumbnailing visual content?