unused-mysql-indexes.md

Show all unused index since the last MySQL server restart (MySQL 5.6+)

SELECT object_schema, object_name, index_name
FROM performance_schema.table_io_waits_summary_by_index_usage 
WHERE index_name IS NOT NULL AND count_star = 0
ORDER BY object_schema, object_name;

SELECT object_schema, object_name, index_name, count_star
FROM performance_schema.table_io_waits_summary_by_index_usage 
WHERE object_schema='my_app' AND index_name='index_bar_on_foo'
ORDER BY object_schema, object_name;