--- a/mysql.rst	Wed Dec 30 11:40:18 2015 +0200
+++ b/mysql.rst	Sat Jan 02 20:10:31 2016 +0200
@@ -76,6 +76,17 @@
   MariaDB [mysql]> SHOW ERRORS;
   MariaDB [mysql]> show engine innodb status;
 
+Debugging quiery performance.
+=============================
+::
+
+  explain select 1;
+
+..
+
+  https://mariadb.com/kb/en/mariadb/explain/
+    Syntax and transcription of EXPLAIN.
+
 Monitor server execution.
 =========================