On Sat, Oct 22, 2016 at 1:54 AM, Robin via arch-general < arch-general@xxxxxxxxxxxxx> wrote: > Hi, > > > I was curious why does 'pacman -Q' operations took longer than 'apt' > > counterparts. > Sounds interesting but I have a few question about how did you measure > this and how big the difference is. (Shouldn't be that big). Would be great > if you provide more information on the comparability of you systems and the > tools you used for tracing. > Maybe there are other reasons why it is slow on your installation ? > > > For long term pacman development road map, it would be better to use > > single sql based database for tracking locally installed packages > > instead of keeping directories of every installed packages. > I am not sure if a sql based database would be a good solution if you > where right. It adds much more complexity and also a dependencies on $SQL > backend. For me as a semi-professional arch user this would be worse than a > maybe "not that fast" package dB querying. > > Regards, > Robin Sometimes I have a similar problem, too. When the system just boots up, or I just exploits my disk (for example building Firefox), pacman-related files are moved out of the disk cache, so it needs some time to read them all from the disk. Here's a simple performance test: $ sudo -v && time pacman -Q linux && sudo sync && sudo sync && echo 3 | sudo tee /proc/sys/vm/drop_caches && time pacman -Q linux [sudo] password for yen: linux 4.8.3-1 pacman --color=auto -Q linux 0.00s user 0.00s system 2% cpu 0.121 total 3 linux 4.8.3-1 pacman --color=auto -Q linux 0.00s user 0.01s system 0% cpu 1.229 total The difference is more than 10 times. I use a 5-year-old HDD. I guess on even older machines things are worse. Regards, Yen Chi Hsuan
