[hollowturtle]

You actually confirmed that rails is slow if the optimization is on the database server and doing data mangling in ruby is less efficient

[runako]

Constructively, I would suggest some areas for study:

- relative speeds of programming languages (https://github.com/niklas-heer/speed-comparison)

- database indexing (https://stackoverflow.com/questions/1108/how-does-database-i...)

- numbers everyone should know (https://news.ycombinator.com/item?id=39658138)

And note that databases are generally written in C.

[hollowturtle]

Constructively, I just wanted to say that you can't claim that something is fast if speed is thanks to something else. OP said people thinks rails is slow but if you have a fast query it's a solved problem. Even python would be fast in this instance with an optimized query

[cultofmetatron]

> Even python would be fast in this instance with an optimized query

I wasn't trying to argue that ruby is slow (it objectively is). I was arguing that its slowness is irrelevant for most webapps because you should be offloading most of the load to your database with efficient queries.

[closeparen]

Unless the database is in your process's address space (SQLite, Datomic, etc) your first problem is going to be shipping the data from the database server to the application process.

[richwater]

You've correctly identified that filtering a list is slower than looking up from an index. Congratulations.

[hollowturtle]

Thank you, let me give you the eli5: I just wanted to say that you can't claim that something is fast if speed is thanks to something else