MySQL查看哪些索引未使用
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
AND OBJECT_SCHEMA <> 'mysql'
ORDER BY OBJECT_SCHEMA,OBJECT_NAME;参考网络资料：https://www.cnblogs.com/cchust/p/5061131.html