MySql performance problems - mysql

Question

This query I have takes a whooping 45 seconds to execute. I have indexes on all fields that are being search.
SELECT SQL_CALC_FOUND_ROWS g.app_group_id, g.id as g_id, p.`id` as form_id,
a.`user` as activity_user,a.`activity` as app_act ,a.*
FROM grouped g
INNER JOIN
(SELECT max(id) as id, app_group_id FROM grouped GROUP BY app_group_id) g1
ON g1.app_group_id = g.app_group_id AND g.id = g1.id
INNER JOIN form p
on p.id = g.id
INNER JOIN
(SELECT a.id, a.date_time, a.user, a.activity FROM log a) a
ON g.id = a.id
WHERE p.agname like '%blahblah%' and p.`save4later` != 'y'
and a.activity = 'APP Submitted' or a.activity = 'InstaQUOTE'
ORDER BY app_group_id DESC limit 0, 100
In my explain it shows im using Using temporary; Using filesort
Indexes are:
activity table: PRIMARY activity_id INDEX date_time INDEX id INDEX activity INDEX user
form table: PRIMARY id INDEX id_md5 INDEX dateadd INDEX dateu INDEX agent_or_underwriter INDEX
grouped table: UNIQUE id INDEX app_group_id INDEX agent_or_underwriter save4later
Any advice is much appreciated
Thank you very much

Answer 1

To start with, try this one:
SELECT
g.app_group_id,
g.id AS g_id,
p.id AS form_id,
a.user AS activity_user,
a.activity AS app_act,
a.id,
a.date_time
FROM grouped g
INNER JOIN
(SELECT MAX(id) AS id, app_group_id FROM grouped GROUP BY app_group_id) g1
ON g1.app_group_id = g.app_group_id AND g.id = g1.id
INNER JOIN form p
ON p.id = g.id
INNER JOIN log a
ON g.id = a.id
WHERE p.agname LIKE '%blahblah%'
AND p.save4later != 'y'
AND a.activity IN('APP Submitted', 'InstaQUOTE')
LIMIT 0, 100
I removed an unnecessary subquery. Also removed ORDER BY. I guess you could do without sorting, and that must speed the query up a lot.
I also removed SQL_CALC_FOUND_ROWS, because, as I mentioned earlier, it should be faster to issue a separate COUNT(*) query.

Answer 2

Your where clause has an "Or" on the "a.Activity". Without ( ) around both activity, it is going through EVERYTHING, all P, G, G1 aliases. I am guessing that might be your bigger issue.
Additionally, I would ensure you have an index on your "Form" table with the ( Save4Later ) column indexed
I would update the query like this:
SELECT STRAIGHT_JOIN SQL_CALC_FOUND_ROWS
g.app_group_id,
g.id as g_id,
QualifyPages.Form_id,
a.`user` as activity_user,
a.`activity` as app_act,
a.*
FROM
( select p.ID as Form_ID
from FORM p
WHERE p.`save4later` != 'y'
AND p.agname like '%blahblah%' ) QualifyPages
JOIN Grouped g
on QualifyPages.Form_ID = g.ID
INNER JOIN
( SELECT app_group_id,
max(id) as MaxIDPerGroup
FROM
grouped
GROUP BY
app_group_id ) g1
ON g.app_group_id = g1.app_group_id
AND g.id = g1.MaxIDPerGroup
INNER JOIN
( SELECT a.id, a.date_time, a.user, a.activity
FROM log a
WHERE a.activity = 'APP Submitted'
or a.activity = 'InstaQUOTE' ) a
ON g.id = a.id
ORDER BY
g.app_group_id DESC
limit
0, 100