[pjungwir]

> I am currently finding Rails view generation to be shockingly slow.

I haven't checked this in a few years, but the last time I looked each `render` call reads the partial off disk, parses it, and executes it.[0] So the common pattern of looping over a collection of objects and rendering a partial for each one is going to hurt a lot. And of course Rails makes tons of allocations, so often you'll see one of those iterations take x00ms as Ruby does some garbage collection.

[0] https://softwareengineering.stackexchange.com/a/365912/29612...

[jrochkind1]

> each `render` call reads the partial off disk, parses it, and executes it

I think it does not do that in 'production' settings, but I'm not sure. I know it does less touching of disk and parsing in production mode, it doens't do all that you mention (that's what the `cache_template_loading` setting controls) -- but I'm not sure it does none of any of that, it may still do things that conceivably seem like they oughta be be cached, not sure.

In default "development" mode settings -- yes, partial template is definitely much slowed down by going to disk and parsing on every request and/or every invocation.

[pjungwir]

I just re-tested on Ruby 3 & Rails 7, and even in development it no longer minds if I rename the erb file in the middle of iterating---so that's an improvement for sure!

I found a Rails issue tracking partial performance in a loop (https://github.com/rails/rails/issues/41452), and it looks like they are still working on improvements. No activity since May though.