rake assets:precompile taking extremely long to complete

Question

In my dev sandbox

RAILS_ENV=production rake assets:precompile

is taking over 4 minutes to complete. Is this normal. On heroku it is taking

Answer 1

We had orders of magnitude speedup using this answer:

EXECJS_RUNTIME='Node' JRUBY_OPTS="-J-d32 -X-C" RAILS_ENV=development bundle exec rake war

http://avinmathew.com/improving-rails-asset-precompile-times-on-jruby/