Ruby On Rails is slow…?

Question

I\'m writing a web application to monitor a furniture factory production flow. It has thousand of data to handle. So far, I run RoR on Mongrel + MySQL and it\'s really really sl

Answer 1

While R-n-R has a reputation of being slow, this sounds too extreme to be a simple problem with the language.

You should run a profiler to determine exactly what functions are slow and why. The most common thing slowing down a web application is the "n+1 problem". That is, when you have n data items in your database, the app makes n separate queries to the database instead of making one query which gets them. But you can't know until you run the profiler. ruby-prof is one profiler I've used.

Edit based on profile results edit:

I firmly believe that you can always remove a query loop. As Mike Woodhouse says, the Rails way to do this is to specify the relations between your tables with a has_many or other association and then let rails automatically generate the table join, this is clear, fast and "the Rails way". But if you are starting out with bare SQL or if the associations don't work in this case, you can simply generate the appropriate joins yourself. And If all else fails, you can create a view or denormalized table which holds the results which previously were found through a loop. Indeed, the fact that you have to iterate through generated queries might be a sign that your table design itself has some flaws.

All that said, if caching your query results works well enough for you, then stay with it. Optimize when needed.