As its getting too slow to complete the push, I am still not sure if I canceled the push operation would be a wise thing to do or not? I am thinking to push later ..
Any one can advice?
The git push is atomic on a per-ref level, which means you won't know what commit was accepted and what was not.
(and that is even more problematic when multiple branches are pushed)
A subsequent push would only push the remaining commits, so if you don't mind having an heroku with an unknown number of commits, you can interrupt and resume later.