Slow mail deliveries using JRuby


Hi All,

I have a problem when sending bulk emails on my Rails 3.2 app with a big
difference in performance compared to the standard MRI 2.1. The problem
seams to be the mail() method invocation inside the mailer class.

Is this mailer problem something known in JRuby, or is just me?

I’m using JRuby 1.7.13.



How many emails are you sending?
Also, are you loading a large amount of records into memory as part of


I’m sending lots of emails, but using paginated results.

I tested the method in both MRI and JRuby with the same amount of data,
and the bottleneck is the Mailer’s mail() render method.

In MRI i’m able to process 20~40 mails per second.

In JRuby 2 or 3.