kellogs's questions

EXPLAIN EXTENDED SELECT SQL_CALC_FOUND_ROWS SQL_NO_CACHE g.*, u.user_id FROM geotable g JOIN userstable u ON g.uid = u.uid
                   -- corners selection:
WHERE (lat BETWEEN ? and ? AND lon BETWEEN ? and ?) ORDER BY time ASC;

回来了

+----+-------------+------------+--------+---------------------+---------+---------+----------------+--------+----------+----------------+
| id | select_type | table      | type   | possible_keys       | key     | key_len | ref            | rows   | filtered | Extra          |
+----+-------------+------------+--------+---------------------+---------+---------+----------------+--------+----------+----------------+
|  1 | PRIMARY     | g          | ALL    | uk_uid,lat_lon_time | NULL    | NULL    | NULL           | 199917 |     2.15 | Using filesort |
|  9 | DERIVED     | u          | eq_ref | PRIMARY             | PRIMARY | 4       | tigasedb.g.uid |      1 |   100.00 |                |
+----+-------------+------------+--------+---------------------+---------+---------+----------------+--------+----------+----------------+

按此顺序在 (lat, lon, time) 列上有一个键。有没有办法说服 MySQL 将它用于此查询？

查询：

EXPLAIN  EXTENDED 
SELECT *, u.user_id 
FROM xgate_geoloc g 
  JOIN tig_users u 
  ON g.uid = u.uid                                    
WHERE 
         -- corners selection:
          ( ( (lat BETWEEN COALESCE(?, lat) and COALESCE(?, lat)) 
          AND (lat NOT BETWEEN COALESCE(?, lat) and COALESCE(?, lat))
            )
         OR ( (lon BETWEEN COALESCE(?, lon) and COALESCE(?, lon)) 
          AND (lon NOT BETWEEN COALESCE(?, lon) and COALESCE(?, lon))
            )
          )
     AND sex = COALESCE(?, sex)
     AND language = COALESCE(?, language)
     AND city = COALESCE(?, city) 
     AND province = COALESCE(?, province) 
     AND country = COALESCE(?, country) 
     AND time BETWEEN COALESCE(?, time) and COALESCE(?, time) 
ORDER BY time DESC 

1. where 表达式中的“OR”对我应该使用的索引有任何影响吗？
2. “时间”字段用于 where 和 order by。在这种情况下有什么办法可以建立索引吗？
3. order by time desc - 降序；又一个无赖

感谢您的输入！

假设 MySQL 的查询缓存在查询的后续执行中以查询中SELECT ... WHERE ... LIMIT x, y唯一不同的参数是 x 和 y 的形式进行检查是否准确？

_ 你好，

我的设置是一个慢速 SSH 到一些 linux 机器。从那里我启动一个 mysql 终端客户端并执行大约 200k 插入（在存储过程内的 while 循环中）。这大约需要 3 个小时才能完成。然而，我的内心告诉我 200k 插入不能花那么长时间（顺便说一句，数据库是空的），所以我猜测数据库的反馈（行打印到终端的标准输入文件描述符）在屏幕上打印得太慢了；首先在 linux 机器上的本地终端上，然后在我的屏幕上更慢，我正在从中进行 SSH。

我当然想关闭来自 mysqld 的所有反馈，以便只有当 mysql 的客户端提示返回时我才能知道插入何时完成。可能比 3 小时快得多。我怎么能那样做？

/etc/my.cnf 如下：

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Default to using old password format for compatibility with mysql 3.x
# clients (those using the mysqlclient10 compatibility package).
old_passwords=1

# Disabling symbolic-links is recommended to prevent assorted security risks;
# to do so, uncomment this line:
# symbolic-links=0

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

遵循存储过程：

    select 'Initializing database..';
call TigInitdb();

-- Possible encodings are:
-- - 'MD5-USERID-PASSWORD'
-- - 'MD5-PASSWORD'
-- - 'PLAIN'
-- More can be added if needed.
call TigPutDBProperty('password-encoding', 'PLAIN');
call TigPutDBProperty('schema-version', '4.0');

select 'Adding new users with PlainPw: ', '+391xxxxxx', 'pwd_xxxxxx';
drop function if exists TigUserGen;

delimiter //

create procedure TigAddUser(_user_id varchar(2049) CHARSET utf8, _user_pw varchar(255) CHARSET utf8)
begin
    declare res_uid bigint unsigned;

    insert into tig_users (user_id, sha1_user_id, user_pw)
        values (_user_id, sha1(lower(_user_id)), _user_pw);

    select LAST_INSERT_ID() into res_uid;

    insert into tig_nodes (parent_nid, uid, node)
        values (NULL, res_uid, 'root');

    if _user_pw is NULL then
        update tig_users set account_status = -1 where uid = res_uid;
    end if;

    select res_uid as uid;
end //

create procedure TigUserGen(usr_count INT)
begin
    DECLARE cnt,len INT;  
    DECLARE usr CHAR(6);  
    SET cnt = 0;
    SET len = 0;
    SET usr = '';  

    WHILE cnt < usr_count DO  
        SET cnt = cnt + 1;
        SET usr = CAST(cnt AS CHAR(6));
        SET len = CHAR_LENGTH(usr);
        CASE len
            WHEN 1 THEN 
                call TigTestAddUser(CONCAT('+39100000', usr), CONCAT('pwd_00000', usr), 'SUCCESS - adding new user', 'ERROR - adding new user');
            WHEN 2 THEN 
                call TigTestAddUser(CONCAT('+3910000', usr), CONCAT('pwd_0000', usr), 'SUCCESS - adding new user', 'ERROR - adding new user');
            WHEN 3 THEN 
                call TigTestAddUser(CONCAT('+391000', usr), CONCAT('pwd_000', usr), 'SUCCESS - adding new user', 'ERROR - adding new user');
            WHEN 4 THEN 
                call TigTestAddUser(CONCAT('+39100', usr), CONCAT('pwd_00', usr), 'SUCCESS - adding new user', 'ERROR - adding new user');
            WHEN 5 THEN 
                call TigTestAddUser(CONCAT('+3910', usr), CONCAT('pwd_0', usr), 'SUCCESS - adding new user', 'ERROR - adding new user');
            ELSE 
                call TigTestAddUser(CONCAT('+391', usr), CONCAT('pwd_', usr), 'SUCCESS - adding new user', 'ERROR - adding new user');
        END CASE;
    END WHILE;  
end //

delimiter ;

call TigUserGen(200000);

谢谢