# Rails3 development mode performance issues

**URL:** <https://www.ruby-forum.com/t/rails3-development-mode-performance-issues/195043>\
**Category:** Rails\
**Created:** [September 15, 2010, 7:06pm UTC](https://www.ruby-forum.com/t/rails3-development-mode-performance-issues/195043 "2010-09-15T19:06:08Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![CUCUCU](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/4af34b/32.png) [@CUCUCU](https://www.ruby-forum.com/u/CUCUCU)\
**Post date:** [September 15, 2010, 7:06pm UTC](https://www.ruby-forum.com/t/rails3-development-mode-performance-issues/195043/1 "2010-09-15T19:06:08Z")

</div>

Hi

I’m developing an app on Rails3. Development mode performance seems to  
be pretty poor, especially on pages involving AJAX and several  
queries. On an AJAX search page, result requests take anything from  
500-600ms to return from the local machine. According to the  
development log, the ActiveRecord portion of the requests is taking \<  
30ms, so I’m pretty sure it’s not inefficient queries.

I’m running Apache/Passenger/Postgresql on the same machine, which is  
a 4ghz Core2Duo with plenty of RAM. In production mode on the same  
database, these requests take 20-25ms. Obviously it’s like comparing  
oranges and apples, but is there any way to optimize development mode  
somehow, without enabling class caching or anything overboard like  
that which would require regular restarts?

---

<div class="post-metadata">

**Author:** ![CUCUCU](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/4af34b/32.png) [@CUCUCU](https://www.ruby-forum.com/u/CUCUCU)\
**Post date:** [September 15, 2010, 7:25pm UTC](https://www.ruby-forum.com/t/rails3-development-mode-performance-issues/195043/2 "2010-09-15T19:25:27Z")

</div>

On Sep 15, 6:04 pm, CU [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> a 4ghz Core2Duo with plenty of RAM. In production mode on the same  
> database, these requests take 20-25ms. Obviously it’s like comparing  
> oranges and apples, but is there any way to optimize development mode  
> somehow, without enabling class caching or anything overboard like  
> that which would require regular restarts?

Rails is reloading all of your app’s code for each request, that takes  
time. Stuff like [GitHub - thedarkone/rails-dev-boost: Speed up slow Rails development mode](http://github.com/thedarkone/rails-dev-boost) does  
exist, don’t know if they work on rails 3.

Fred