Optimizer Trace walkthrough

This video was presented at the MariaDB Server Fest, held online from 14-20 September 2020.

Q&A links

Other links


Optimizer Trace was introduced in MariaDB 10.4, the previous release. During the past year, it has received numerous updates and improvements.

The talk is a walkthrough of all kinds of information that one can find in the Optimizer Trace, and shows how to use it to diagnose common and not so common optimizer issues.

I will also compare MariaDB’s Optimizer Trace with MySQL’s optimizer trace, and discuss further development directions for it.


Sergei Petrunia is query optimizer developer at MariaDB Corporation. He has implemented the ANALYZE feature in MariaDB, and contributed to Optimizer Trace, Window Functions, subquery optimizations, and other query optimizer features.

Date and time

  • Paris: Tuesday 15 September, 14.10 – 14.55 CEST (UTC +2)
  • New York: Wednesday September 16, 14.40 – 15.25 / 2.40pm – 3.25pm EDT (UTC -4)
  • Beijing / Singapore: Friday 18 September, 17.55 – 18.35 CST / SGT (UTC +8)