Blocking friends sql (super slow sql??)

StackOverflow https://stackoverflow.com/questions/5056401

Question

Hi im having trouble with this sql. Basically it displays statuses that my friends posted, and it filters out the friends that i blocked.

The sql is slooooowwwwwww though.. It takes 2 seconds to process it. What seems to be the problem. (ive listed the tables and some examples of how it looks below the sql) thanks in advance! The sql....

SELECT from_user_id,content,wall.date, wall.wall_type, users.id, users.displayname 
            FROM wall

            INNER JOIN friendship ON ( wall.from_user_id =friendship.user_a OR wall.from_user_id = friendship.user_b ) 
            INNER JOIN users ON (wall.from_user_id = users.id)WHERE users.id not in (select blocked_id from blocklist where user_id = 1) and (wall.wall_type = 'home' OR wall.wall_type = 'profile' or wall.wall_type = 'topro') AND (
                  (friendship.user_a = 1 and friendship.user_b = wall.from_user_id)
                or  
                    (friendship.user_a = wall.from_user_id and friendship.user_b = 1)    or (wall.user_id_of_wall = 1 or type_id = 1 or from_user_id = 1))GROUP BY wall_id ORDER BY date DESC LIMIT 10

(table name: blocklist)

    user_id | blocked_id
        1     74
        1     70
        1     94
        1     81

(table name:friendhip)

user_a   user_b status  date
1        93         1   1297323354
1        79         1   1297323409
1        81         1   1297323403
1        82         1   1297323398
1        85         1   1297323389
1        90         1   1297323367
1        89         1   1297323373

(table name:users)

       id   displayname
        1   Kenny  Jack
        8   Wale Robinson
        7   Victor WIlliams
        6   Micheal Harris
        9   Micheal Boston
        10  Yestor Smith

the wall table

wall_id wall_type   user_id_of_wall   type_id   from_user_id    content      viewed   date
   5    profile        8                    8          8         Just chilling! 0   1296858001

THANKS!!!

Was it helpful?

Solution

NOT IN is used for fixed values, use NOT EXISTS instead :

SELECT from_user_id,content,wall.date, wall.wall_type, users.id, users.displayname 
            FROM wall

            INNER JOIN friendship ON ( wall.from_user_id =friendship.user_a OR wall.from_user_id = friendship.user_b ) 
            INNER JOIN users ON (wall.from_user_id = users.id)
WHERE not exists (select * from blocklist where users.id = blocked_id AND user_id = 1) and wall.wall_type IN ('home', 'profile', 'topro') AND (
                  (friendship.user_a = 1 and friendship.user_b = wall.from_user_id)
                or  
                    (friendship.user_a = wall.from_user_id and friendship.user_b = 1)    or (wall.user_id_of_wall = 1 or type_id = 1 or from_user_id = 1))
GROUP BY wall_id
ORDER BY date DESC LIMIT 10

[EDIT] Use IN for fixed values (wall_type)...

OTHER TIPS

always use WITH (NOLOCK) on read-only queries!

also, please remove all your paranthesis on your JOIN clause, did you copy and paste this from MS Access?

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