Mailinglist Archive: opensuse (982 mails)

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Re: [opensuse] Re: [opensuse-factory] How many seconds does "time rpm -qa | wc" cost it?
On 2014-09-15 23:10, Bernhard Voelker wrote:

So the question is if the pread()s could be enhanced/avoided.

I suppose that the entire database could be loaded in memory and then
processed. This was not feasible 15 years ago, but now it is. Probably
there are functions to map an entire file in RAM - I think that "map" is
the current name. And it only needs to be loaded for some limited time.

Or force the system to cache it by copying it to null...

Look, it is as simple as this:

cer@Telcontar:~> time cp /var/lib/rpm/Packages /dev/null

real 0m3.560s
user 0m0.003s
sys 0m0.188s

cer@Telcontar:~> time cp /var/lib/rpm/Name /dev/null

real 0m0.067s
user 0m0.000s
sys 0m0.001s
cer@Telcontar:~> time rpm -qa | wc -l

real 0m3.191s
user 0m2.685s
sys 0m0.200s

It runs now in seconds, not minutes.

Cheers / Saludos,

Carlos E. R.
(from 13.1 x86_64 "Bottle" at Telcontar)

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