The database is located here: /home/user/.cache/tracker/meta.db

The programs currently accessing that file:

RM696-40-4_PR_005:~# lsof +c 15 /home/user/.cache/tracker/meta.db|awk '{print $1}'
COMMAND
feedengine
tracker-store
tracker-store
tracker-store
contactsd
call-history
commhistoryd
messaging-ui
tracker-miner-f
smartsearch
tracker-writeba
contacts
camera-ui
feedreader

Last, but not least:

RM696-40-4_PR_005:~# sqlite3 /home/user/.cache/tracker/meta.db
SQLite version 3.7.7 2011-06-23 19:49:22
Enter ".help" for instructionsinstructions
Enter SQL statements terminated with a ";"
sqlite> pragma integrity_check;
Error: no such collation sequence: TRACKER
sqlite> .q

Btw the fille is over 70mb. I Have tried to export/re-import it (which shrank the size to 20Mb after throwing out a lot of invalid entries); unfortunately, couldn't figure out how to get the new DB working, since some of the processes accessing the file cannot be killed without immediately respawning.