Load test cohort uploading.
We should have boundaries on how big a cohort can be to be updated successfully.
I had a question that required looking up data for a large cross-wiki cohort and I gave Wikimetrics a try. The cohort upload failed prior to validation. The CSV was a 11Mb list of 630K user_id,project_id pairs.
The error I received is "Error! Server error while processing your upload”. The cohort metadata were created (cohort name: mnru_201307_201406) but it appears to be empty.