Need help debugging a "result has been cleared" exception
In one of my projects at work we've set up a loadtesting environment for a rails application. Within this environment I'm seeing frequent (but apparently non-determinisic) PGError (result has been cleared) exceptions. I'm a bit stumped, since I haven't seen these ever before; not in another environment for this project, nor in any other postgres related ruby project ever...
The basic project parameters: ruby 2.0.0 p0 (will try upgrading to p195 and see if that changes anything), pg 0.15.1, rails 3.2.13, unicorn, postgres 9.2.4 running on a 64 bit CentOS 5.8.
Differences in our environments: Production uses physical machines, has pg compiled against libpq for postgres 9.2.1 (version mismatch on the patchlevel; .1 client vs .4 server), postgres is running in a default locale. Loadtest is running in VMWare based virutal machines, pg is compiled against libpq for postgres 9.2.4 (version match), postgres is running in a german locale.
To be honest I'm a bit stumped. Are there in your experience likely culprits, and how would I go about trying to find the underlying issue?
Any input and ideas are welcome!