the cause (on pry, irb, or source code), this line runs in 40-45 seconds:
DataMapper.setup(:default, 'postgres://myuser:[email protected]/mydbname')
additional info: http://stackoverflow.com/questions/19397577/slow-ruby-datamapper-setup
The host (Ubuntu with Intel i3 CPU): Linux 3.8.0-31-generic #46-Ubuntu SMP Tue Sep 10 20:03:44 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
The guest (ArchLinux, inside VMWare): Linux 3.11.1-2-ARCH #1 SMP PREEMPT Sun Sep 22 20:03:40 CEST 2013 i686 GNU/Linux
VMWare: 6.0.0 build-1295980
PostgreSQL: postgres (PostgreSQL) 9.3.1
dm-postgres-adapter: dm-postgres-adapter (1.2.0)
Ruby: ruby 2.0.0p247 (2013-06-27 revision 41674) [i686-linux]
JRuby: jruby 1.7.5 (1.9.3p392) 2013-10-07 74e9291 on OpenJDK Client VM 1.7.0_40-b60 [linux-i386]
slowness does not happened when using ActiveRecord, psql command line or when running the same guest on another host PC (ArchLinux with AMD APU CPU)