Reasoning about “complicated” Postgres SQL queries

Posted on by David Vassallo

TL;DR When building non-trivial SQL queries, it helps to: State your objective in as "declarative" a way as possible Work from the "inside out". When using subqueries in SQL it helps to find the innermost nested subquery and work your way outwards to figure out what is going on. Similarly, I find that when building … Continue reading Reasoning about “complicated” Postgres SQL queries

Grafana Prometheus: Detecting anomalies in time series

Posted on by David Vassallo

In our previous post, we explored how we detect anomalies in time series using the 3 sigma rule using Influx. In this article we'll do the same using Grafana https://blog.davidvassallo.me/2021/09/28/influxdb-flux-detecting-anomalies-in-time-series/ As a quick recap, the 3-sigma rule states that approximately all our "normal" data should be within 3 standard deviations of the average value of … Continue reading Grafana Prometheus: Detecting anomalies in time series