Avoid domain user lookups

[kou1okada]

Avoid domain user lookups

[kou1okada]

Thank you for useful advice for my fork.

I added --numeric-owner option to issue-39 branch.

Can you review performance improvement about 4498eca on issue-39 branch ?

I measured performance by below commands:

# Prepare a package to measure performance
# Currently, cygwin-doc has 12 folders and 956 files.
# If this package is not enough to measure performance,
# please choose another one which is enough to measure performance.
pkg=cygwin-doc

# Cache a $pkg package to cygwin cache folder
apt-cyg remove $pkg 
apt-cyg install $pkg

# Prepare branches
git clone https://github.com/kou1okada/apt-cyg -b master /tmp/apt-cyg-master
git clone https://github.com/kou1okada/apt-cyg -b issue-39 /tmp/apt-cyg-issue-39

# Measure performance without this patch
apt-cyg remove $pkg
time /tmp/apt-cyg-master/apt-cyg -u install $pkg

# Measure performance with this patch
apt-cyg remove $pkg
time /tmp/apt-cyg-issue-39/apt-cyg -u install $pkg

A result on my environment (sorry, I have no environment with Active Directory) was below:

$ time /tmp/apt-cyg-master/apt-cyg -u install $pkg
...
real    0m5.693s
user    0m0.761s
sys     0m1.796s

$ time /tmp/apt-cyg-issue-39/apt-cyg -u install $pkg
...
real    0m5.598s
user    0m0.669s
sys     0m1.408s

Best regard.

[ilatypov]

The delay in a single tar xvf would measure as noticeable seconds when the tarball has a user ID not present in /etc/passwd and net users /domains shows thousands users. I forgot the exact mechanism Cygwin relies on in resolving user IDs and whether it is configurable.

The --numeric-owner option could apply to all tar xvf invokations such as unpacking the actual packages.

[kou1okada]

Hmm, thanks.
I want to know the quantitative benefit of the performance.
And I hope there is no side effect.

[kou1okada]

4498eca was merged to master.