dpkg is pretty slow in Debian-based systems, usually because of the many files which are stored in the /var/lib/dpkg/info folder. To speed up things, Luca Bruno created a project called tdpkg which uses an sqlite3 or tokyocabinet database for loading the dpkg .list files in the /var/lib/dpkg/info folder which makes dpkg a lot faster.
The author (Luca Bruno) says that:
I've managed to bring cold startup time from about 14 seconds down to about 2 seconds. I will definitely have fun installing and removing applications back again.