这些读数是否适用于~500 CCU的应用？

Question

The server is setup with the site (PHP + MariaDB + Nginx) on the frontend connected to a websocket server (Node.js + socket.io) in the backend. The node.js server is on the left and the LEMP stack is on the right. I'm getting unusually high CPU usage from MySQL, I'm not sure though if this is normal since I do have an 8 core CPU.

https://gyazo.com/9b3a7e740360c79623ab7d58f1b9d9ca

MySQL idles at 5-10% CPU usage, and this happens under load. MySQL maxes out at around 200% CPU usage under load, but it seems to be balanced among the 8 cores. I'm just wondering, is this normal behaviour? If not, what can I do to figure out what's causing it?

Answer 1

High CPU is almost always caused by inefficient queries, possibly involving missing or inadequate indexes.

SHOW FULL PROCESSLIST, then show us the slow queries, plus EXPLAIN SELECT ... and SHOW CREATE TABLE.