严重的MySQL性能问题(连接,临时表,Filesort ....)

您可以执行UNION of 2查询而不是OR.我知道在至少一个其他DBMS中这个速度快一个数量级的实例,并且我猜测MySQL的查询优化器可能共享相同的"特性".

SELECT  whatever
FROM    votes v
        INNER JOIN
                users u
                ON v.user_id_1 = u.uid
WHERE   v.user_id_2 = 9834
AND     v.votes_2 = 0

UNION

SELECT  whatever
FROM    votes v
        INNER JOIN
                users u
                ON v.user_id_2 = u.uid
WHERE   v.user_id_1 = 9834
AND     v.votes_1 = 0

ORDER BY updated_at DESC