Scan for new items takes ages after syncing collection btw. two computers

[news@tcrass.de]

Hi there,

there's one thing I've been wondering about for quite a while:

I use unison (https://www.cis.upenn.edu/~bcpierce/unison/ -- great 
tool!) for syncing my photo collection (including digikam4.db) between 
desktop and laptop computer. I take great care not to add or edit photos 
on both computers simultaneously, so every syncing process is actually a 
clean copy operation from one machine to the other. Yet, when, after 
syncinc, I launch digikam on the target machine, it apparently does a 
full scan of all items in the collection, which takes ages, even if only 
a few photos have actually been added or changed. However, when 
re-launching digiakm on the same machine without immediately preceeding 
sync, the new items scan takes only a few seconds.

So how does digikam decide which folders and images are to be 
re-scanned? How can digikam possibly 'know' that there has been going on 
something else than just local file changes?

The only idea I came up with is that digikam might somehow detects the 
changes in its database file's meta data (like file size, access time, 
md5 hash value...) with respect to its last run on the same machine 
which were introduced during syncing.

Any comments appreciated!

Cheers --

-- Torsten