Collection with old stats not working

[Jeff Mitchell]

Quoting Lorenz Röhrl <l_roehrl at web.de>:

> Btw: Scanning for changed files with enabled ATF takes very long (longer as
> without ATF), looks as amarok is doing a full rescan?

This should only be the case if you have a *very* large number of  
files in your Playlist, as well as a *very* large number of changed  
files and probably with a *very* large number of disabled playlist  
items (i.e. items that are not found).  Even then it *shouldn't* be  
the case, just a *could* be the case.

With ATF, when an incremental scan is done, the Playlist is sent  
notification of any changed files.  It does one of two things:

1) If a uniqueid has changed, it looks in a map of  
uniqueid-to-playlistitem-pointers to see if it has an item with that  
uniqueid; if so it notifies the item of the change.

2) If a url has changed, it looks in the disabled children to see if  
there is a match for the URL.  Because we do not expect many disabled  
children at any given time this is a list of pointers rather than a  
map, which helps keep memory use down.

So in the extremely unlikely circumstance that you have a huge number  
of changed URLs coupled with a huge number of disabled playlist items  
you could potentially hit a bad scenario.

Other than that, incremental scans with ATF enabled should take about  
the same amount of time as scans without ATF enabled.  ATF doesn't  
change which files are looked at, it just does a few more things with  
some of the metadata -- and that only if the metadata has changed.

--Jeff