PostgreSQL error

Hi All,
I’m seeing intermittent Postgres errors in my rails app that are
resulting
in very long-running requests. I’ve googled this error, but all the
results
points to a problem with an earlier version of Rails that has supposedly
been fixed, or to problems with gems I’m not using (Sideqik) . This is a
low-traffic application, and I can’t see any pattern as to when the
errors
occur.

I’m running the following:
Rails 4.2.1
pg gem 0.18.2
ruby 2.2.0
Postgres 9.1.11, with max_connections=200, current connections ~90
Ubuntu 14.04.2
Passenger 5.0.8

The error is PG::UnableToSend (SSL SYSCALL error: EOF detected)
Stacktrace here
https://gist.github.com/christopher-b/7cea858ff7008b85d353
.

Anyone have any idea what might be causing this, or how to track down a
solution? Thanks!