From: khaines@...
Date: 2007-03-07T20:24:34+09:00
Subject: Re: High ActiveRecord CPU Utilization

On Wed, 7 Mar 2007, Brian Adkins wrote:

> When running a test that primarily involves loading up a few MySQL tables 
> with ActiveRecord objects, I was surprised to see the Ruby CPU utilization at 
> 93% and the MySQL CPU utilization at 7%. I would expect this workload to be 
> heavier on MySQL than that.
>
> I would think inserts (particularly with updating several foreign key 
> indices) would tax the database more than Ruby.
>
> Has this been other folks' experience? Is running in the test environment 
> incredibly different than production with respect to CPU utilization? I 
> suppose my next step is to run in production to see what kind of results I 
> get.

No, that isn't surprising.  Any ORM trades CPU utilization outside of the 
database for convenience in the data representation.  AR is fairly 
heavyweight in that regard, so it's doing a lot of work to give you the 
API that it does.  Latency to a database can be a significant bottleneck 
to some applications, but relatively speaking, CPU utilization by the db 
will usually be a small fraction of the CPU utilization of the ORM using 
application that is talking with the db.


Kirk Haines