~$ time zypper pa -i

real    0m11.357s
user    0m9.392s
sys     0m0.212s

but

~$ time zypper --disable-repositories pa -i

real    0m1.061s
user    0m0.837s
sys     0m0.153s


rpm -qa is also faster compared to plain 'zypper pa -i'

It seems that the 'zypper pa' command also performs some repository operations
which slows down the overall process. Since we are only interested in the
installed packages, perhaps this can be optimized a little bit and not perform
unnecessary network or repository operations.