How do I diagnose a slow performing Postgres database on Heroku?

Question

We have a rails app on Heroku with the Postgres add on.

In isolation no one query performs out of the norm. However in production some read queries perform very badly.

Currently I can only assume that it's the combination of concurrent queries that is causing a slow down. But, how can I prove this and diagnose further?

NewRelic is just telling me that a query is slow. But I know it's slow. My hypothesis is not that the queries are too slow, but rather that the db server is under too heavy a load. But are there any tools that would tell me that for sure?

Thanks!

Answer 1

NewRelic tells you several details about slow queries, including query analysis and explanation.

However, that report is not available in all plans. http://newrelic.com/pricing/details

Check your plan details. In case your plan doesn't include it, you may want to upgrade for one month to identify the issue and take action, then you can downgrade again.