Query Metrics Requirements for MySQL

Let’s answer a question which, to my knowledge, has never been systematically addressed: What are the requirements for a production-ready query metrics app at scale? I am uniquely qualified to answer that because I have written four query metrics apps, two of which are the open-source standard for MySQL: pt-query-digest and the original (v1) code behind the query metrics/analysis part of Percona Monitoring and Management. I’ve also published a couple of packages related to query metrics: go-mysql/slowlog and go-mysql/query. Read more...