Optimize GROUP BY&ORDER BY query
- by Jan Hancic
I have a web page where users upload&watch videos. Last week I asked what is the best way to track video views so that I could display the most viewed videos this week (videos from all dates).
Now I need some help optimizing a query with which I get the videos from the database. The relevant tables are this:
video (~239371 rows)
VID(int), UID(int), title(varchar), status(enum), type(varchar), is_duplicate(enum), is_adult(enum), channel_id(tinyint)
signup (~115440 rows)
UID(int), username(varchar)
videos_views (~359202 rows after 6 days of collecting data, so this table will grow rapidly)
videos_id(int), views_date(date), num_of_views(int)
The table video holds the videos, signup hodls users and videos_views holds data about video views (each video can have one row per day in that table).
I have this query that does the trick, but takes ~10s to execute, and I imagine this will only get worse over time as the videos_views table grows in size.
SELECT
v.VID,
v.title,
v.vkey,
v.duration,
v.addtime,
v.UID,
v.viewnumber,
v.com_num,
v.rate,
v.THB,
s.username,
SUM(vvt.num_of_views) AS tmp_num
FROM
video v
LEFT JOIN videos_views vvt ON v.VID = vvt.videos_id
LEFT JOIN signup s on v.UID = s.UID
WHERE
v.status = 'Converted'
AND v.type = 'public'
AND v.is_duplicate = '0'
AND v.is_adult = '0'
AND v.channel_id <> 10
AND vvt.views_date >= '2001-05-11'
GROUP BY
vvt.videos_id
ORDER BY
tmp_num DESC
LIMIT
8
And here is a screenshot of the EXPLAIN result:
So, how can I optimize this?
