At what point does scalability become an issue for a Rails application deployed on Heroku? -

At what point does scalability become an issue for a Rails application deployed on Heroku? -

ruby on rails has largely been faulted it's lack of scalability options, , alternative migrate form of java webapp or similar. of concerns seem arbitrary @ best, in way.

are there concrete numbers when application needs rewritten in different language? heroku provides various scaling options numbers of dynos available app, @ point diminishing returns, if any, evident? or @ point cost of having many dynos outweigh costs of writing new app?

how many active concurrent users can expect able back upwards without suffering performance issues on basic free hosting plan @ heroku?

the "rails doesn't scale" myth won't die ...

quoting twitter's lead architect:

the performance boosts associated “faster” language give 10-20% improvement, architectural changes ruby , rails happily accommodated, twitter 10000% faster.

i can't give fixed number, absolutly guaranteed run database or architectural bottlenecks long long before ruby or rails starting become bottlenecks.

teflon ted has created a nice collection of blog posts regarding topic.

ruby-on-rails heroku scalability