ishmael.wikimedia.org

ishmael.wikimedia.org.

http://ishmael.wikimedia.org is a visual tool that shows MySQL statistics and lets you analyze MySQL query logs. Wikimedia Foundation staff can authenticate with their credentials for this wiki to view Ishmael.

MySQL's slow query log is a file local to the DB that requires shell access to the db server - http://dev.mysql.com/doc/refman/5.0/en/slow-query-log.html describes it. Asher set up ishmael, a web tool to analyze slow queries, circa 2011.

In 2013, Asher wrote:

if you're interested in production query performance histograms, I recommend looking at those generated from random samples of all queries in addition to just those that make the slow query logs.

Links to both of those views for every db are provided on http://noc.wikimedia.org/dbtree/ .