It’s time to resume blogging. Starting with a bit of stale news: yours truly had two talks at MariaDB Fest . The first one was the Optimizer Trace Walkthrough (video, slides). The talk covers Optimizer Trace in MariaDB and it has a comparison with MySQL’s Optimizer Trace.
One interesting thing I’ve learned while presenting was that Øystein Grovlen has made a tool to summarize information from the trace – https://github.com/ogrovlen/opttrace.
Its main use case is analyze the join optimizer’s actions: it prints a condensed summary about what join order prefixes were considered and the reason they were discarded.
The tool doesn’t work with MariaDB, because MariaDB’s trace is slightly different. If I get a support escalation about a join optimization problem, I might try to get opttrace to work with MariaDB’s traces.
Sergei Petrunia's blog 