pacman -Sy vs pacman -Syy

ibendiben · 2008-02-10 12:22:27

I've been curious for this some time now: Why does the 'refresh' process take noticeably longer when all packages are up-to-date?
So I took it for a test:

time -p (sudo pacman -Syy)
:: Synchronizing package databases...
testing 23,3K 53,0K/s 00:00:00 [---------------------] 100%
core 23,8K 56,1K/s 00:00:00 [---------------------] 100%
extra 310,4K 123,0K/s 00:00:03 [---------------------] 100%
community 340,5K 142,7K/s 00:00:02 [---------------------] 100%
local database is up to date
real 22.32
user 0.38
sys 2.39

Immidiately afterwarts I run:

time -p (sudo pacman -Sy)
:: Synchronizing package databases...
testing is up to date
core is up to date
extra is up to date
community is up to date
local database is up to date
real 109.62
user 0.01
sys 0.10

That's 5 times slower!!
Now why is this?... and when this isn't hard to answer (which I suspect) why is pacman -Sy there?

wonder · 2008-02-10 12:26:18

i think because -Sy compares the files to see if you have the latest and -Syy doesn't compare it, just rewrite it.

ibendiben · 2008-02-10 12:28:15

That's what I thought... but there no need for this if you can just refresh everything in less time, is there?

Allan · 2008-02-10 13:05:00

Well, -Syy is a lot slower on my system. I don't have testing enabled, though I really can't see that making a difference. I am reading correctly that it takes just under two minutes on your computer to do a "pacman -Sy". Does running "pacman-optimize" speed this up any?

allan@arch ~
> time -p (sudo pacman -Syy)
:: Synchronizing package databases...
 core                      23.8K   58.2K/s 00:00:00 [#####################] 100%
 extra                    310.4K   58.9K/s 00:00:05 [#####################] 100%
 community                340.5K   58.5K/s 00:00:06 [#####################] 100%
 local database is up to date
real 15.35
user 0.24
sys 0.88

allan@arch ~
> time -p (sudo pacman -Sy)
:: Synchronizing package databases...
 core is up to date
 extra is up to date
 community is up to date
 local database is up to date
real 2.64
user 0.01
sys 0.01

ibendiben · 2008-02-10 13:24:42

sudo pacman-optimize
==> MD5sum'ing the old database...
==> Tar'ing up /var/lib/pacman/...
==> Making and MD5sum'ing the new db...
==> Checking integrity...
==> Putting the new database in place...

==> Finished. Your pacman database has been optimized.
==> For full benefits of pacman-optimize, run 'sync' now.

sync

time -p(sudo pacman -Sy)
:: Synchronizing package databases...
 testing is up to date
 core is up to date
 extra                    310,4K  127,3K/s 00:00:02 [---------------------] 100%
 community is up to date
 local database is up to date
real 73.50
user 0.16
sys 0.77

time -p(sudo pacman -Sy)
:: Synchronizing package databases...
 testing is up to date
 core is up to date
 extra is up to date
 community is up to date
 local database is up to date
real 109.65
user 0.01
sys 0.07

So the question should be: Why is pacman -Sy that slow on my system?

Allan · 2008-02-10 13:29:33

Well, what is your system, filesystem type, free space, fragmentation level, and... well, that should do for a start!

ibendiben · 2008-02-10 16:17:06

You got a nice command for that?

Arch Linux

#1 2008-02-10 12:22:27

pacman -Sy vs pacman -Syy

#2 2008-02-10 12:26:18

Re: pacman -Sy vs pacman -Syy

#3 2008-02-10 12:28:15

Re: pacman -Sy vs pacman -Syy

#4 2008-02-10 13:05:00

Re: pacman -Sy vs pacman -Syy

#5 2008-02-10 13:24:42

Re: pacman -Sy vs pacman -Syy

#6 2008-02-10 13:29:33

Re: pacman -Sy vs pacman -Syy

#7 2008-02-10 16:17:06

Re: pacman -Sy vs pacman -Syy

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