Looking at the scale testing postgresql logs I can see that we are repeatedly calculating the latest_report_id from the reports table. This happens every time we insert a report but we should not need to recalculate the latest_report every time.
We should store the latest_report_timestamp ( the producer_timestamp from reports ) in certnames with the latest_report_id. Then when we insert a new report we can compare the producer timestamp to the latest_report_timestamp and update the latest_report_id and _timestamp if it is actually the latest report.
This would eliminate an expensive query that sorts all of the reports for a certname just to find the most recent report.