mysql联接优化大查询

Question

i have big query like this and i can't totally rebuild application because of customer:

SELECT count(AdvertLog.id) as count,AdvertLog.advert,AdvertLog.ut_fut_tstamp_dmy as day,
          AdvertLog.operation,
          Advert.allow_clicks,
          Advert.slogan as name, 
          AdvertLog.log,
                        (User.tx_reality_credit
            +-20
            -(SELECT COUNT(advert_log.id) FROM advert_log WHERE ut_fut_tstamp_dmy <= day AND operation = 0 AND advert IN (168))
            +(SELECT IF(ISNULL(SUM(log)),0,SUM(log)) FROM advert_log WHERE ut_fut_tstamp_dmy <= day AND operation IN (1, 2) AND advert = 40341 )) AS points 
FROM `advert_log` AS AdvertLog
LEFT JOIN `tx_reality_advert` Advert ON Advert.uid = AdvertLog.advert
LEFT JOIN `fe_users` AS User ON (User.uid = Advert.user or User.uid = AdvertLog.advert)
WHERE User.uid = 40341 and AdvertLog.id>0
GROUP BY AdvertLog.ut_fut_tstamp_dmy, AdvertLog.advert
ORDER BY AdvertLog.ut_fut_tstamp_dmy_12 DESC,AdvertLog.operation,count DESC,name
LIMIT 0, 15

It takes 1.5s approximately which is too long.

Indexes:

User.uid
AdvertLog.advert
AdvertLog.operation
AdvertLog.advert
AdvertLog.ut_fut_tstamp_dmy
AdvertLog.id
Advert.user
AdvertLog.log

Output of Explain:

id  select_type table   type    possible_keys   key key_len ref rows    Extra
1       PRIMARY User    const    PRIMARY    PRIMARY 4       const 1     Using temporary; Using filesort
1       PRIMARY AdvertLog range  PRIMARY,advert PRIMARY 4   NULL 21427  Using where
1       PRIMARY Advert  eq_ref   PRIMARY    PRIMARY 4   etrend.AdvertLog.advert 1   Using where
3   DEPENDENT SUBQUERY  advert_log  ref ut_fut_tstamp_dmy,operation,advert  advert  5   const   1   Using where
2   DEPENDENT SUBQUERY  advert_log  index_merge ut_fut_tstamp_dmy,operation,advert  advert,operation    5,2 NULL    222 Using intersect(advert,operation); Using where

Can anyone help me, because i tried different things but no improvements

Answer 1

The query is pretty large, and I'd expect this to take a fair bit of time, but you could try adding an index on Advert.uid, if it's not present. Other than that, someone with much better SQL-foo than I will have to answer this.

Answer 2

First, your WHERE clause is based on a specific "User.ID", yet there is an index on the Advert_Log by the Advert (user ID). So, first, change the WHERE clause to reflect this...

Where 
   AdverLog.Advert = 40341

Then, remove the "LEFT JOIN" to just a "JOIN" to the user table.

Finally (without a full rewrite of the query), I would tack on the "STRAIGHT_JOIN" keyword...

select STRAIGHT_JOIN
    ... rest of query ...

Which tells the optimizer to perform the query in the order / relations explicitly stated.

Another area to optimize would be to pre-query the "points" (counts and logs based on advert and operation) once and pull the answer from that (as a subquery) instead of it running through two queries)... but I'd be interested to know impact of above WHERE, JOIN and STRAIGHT_JOIN helps.

Additionally, looking at the join to the user table based on EITHER The Advert_Log.Advert (userID), or the TX_Reality_Credit.User (another user ID which does not appear to be the same since the join between Advert_Log and TX_Reality_Credit (TRC) is based on the TRC.UID) unless that is an incorrect assumption. This could possibly give erroneous results as you are testing for MULTIPLE User IDs... the advert user, and whoever else is the "user" from the "TRC" table... which would result in which user's credit is being applied to the "points" calculation.

To better understand the relationship and context, can you give some more clarification of what is IN these tables from the Advert_Log to TX_Reality_Credit perspective, and the Advert vs UID vs User...