On Sat, 22 Oct 2016 04:06:31 +0000 Alive 4ever <alive4ever@xxxxxxxx> wrote: > On Sat, Oct 22, 2016 at 02:15:01AM +0800, Chi-Hsuan Yen via arch-general wrote: > > 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 > > My own test - before optimization, ``pacman -Qs linux`` took almost half > a minute. > $ time pacman -Qs linux > real 0m26.716s > user 0m0.063s > sys 0m0.230s > > After running ``pacman-optimize``, it runs instantly. > $ time pacman -Qs linux > real 0m0.048s > user 0m0.030s > sys 0m0.017s > > The filesystem fragmentation can be felt more deeply on slower and older > HDD. HUmm just tried that and the results were exactly the same before and after pacman-optimise . All you have done the second run is read the cache which is obviously a lot quicker than hunting it out on an actual HDD . Pete .
