我有以下簡單的MySQL查詢:簡單的MySQL查詢問題
SELECT SQL_NO_CACHE mainID
FROM tableName
WHERE otherID3=19
AND dateStartCol >= '2012-08-01'
AND dateStartCol <= '2012-08-31';
當我運行這個需要0.29秒帶回36074個結果。當我增加日期以帶回更多結果時(65703),它運行在0.56。當我在同一臺服務器上但在不同的表上運行其他類似的SQL查詢時(某些表更大),結果大約在0.01秒後回來。
雖然0.29並不慢 - 這是複雜查詢的基本部分,並且此計時意味着它不可縮放。
請參閱下面的表格定義和索引。
我知道這不是服務器負載,因爲我在開發服務器上有相同的問題,使用很少。
+---------------------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------------------+--------------+------+-----+---------+----------------+
| mainID | int(11) | NO | PRI | NULL | auto_increment |
| otherID1 | int(11) | NO | MUL | NULL | |
| otherID2 | int(11) | NO | MUL | NULL | |
| otherID3 | int(11) | NO | MUL | NULL | |
| keyword | varchar(200) | NO | MUL | NULL | |
| dateStartCol | date | NO | MUL | NULL | |
| timeStartCol | time | NO | MUL | NULL | |
| dateEndCol | date | NO | MUL | NULL | |
| timeEndCol | time | NO | MUL | NULL | |
| statusCode | int(1) | NO | MUL | NULL | |
| uRL | text | NO | | NULL | |
| hostname | varchar(200) | YES | MUL | NULL | |
| IPAddress | varchar(25) | YES | | NULL | |
| cookieVal | varchar(100) | NO | | NULL | |
| keywordVal | varchar(60) | NO | | NULL | |
| dateTimeCol | datetime | NO | MUL | NULL | |
+---------------------------+--------------+------+-----+---------+----------------+
+--------------------+------------+-------------------------------+--------------+---------------------------+-----------+-------------+----------+--------+------+------------+---------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |
+--------------------+------------+-------------------------------+--------------+---------------------------+-----------+-------------+----------+--------+------+------------+---------+
| tableName | 0 | PRIMARY | 1 | mainID | A | 661990 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_otherID1 | 1 | otherID1 | A | 330995 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_otherID2 | 1 | otherID2 | A | 25 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_otherID3 | 1 | otherID3 | A | 48 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_dateStartCol | 1 | dateStartCol | A | 187 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_timeStartCol | 1 | timeStartCol | A | 73554 | NULL | NULL | | BTREE | |
|tableName | 1 | idx_dateEndCol | 1 | dateEndCol | A | 188 | NULL | NULL | | BTREE | |
|tableName | 1 | idx_timeEndCol | 1 | timeEndCol | A | 73554 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_keyword | 1 | keyword | A | 82748 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_hostname | 1 | hostname | A | 2955 | NULL | NULL | YES | BTREE | |
| tableName | 1 | idx_dateTimeCol | 1 | dateTimeCol | A | 220663 | NULL | NULL | | BTREE | |
| tableName | 1 | idx_statusCode | 1 | statusCode | A | 2 | NULL | NULL | | BTREE | |
+--------------------+------------+-------------------------------+--------------+---------------------------+-----------+-------------+----------+--------+------+------------+---------+
explain輸出:
+----+-------------+-----------+-------+----------------------------------+-------------------+---------+------+-------+----------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+-----------+-------+----------------------------------+-------------------+---------+------+-------+----------+-------------+
| 1 | SIMPLE | tableName | range | idx_otherID3,idx_dateStartCol | idx_dateStartCol | 3 | NULL | 66875 | 75.00 | Using where |
+----+-------------+-----------+-------+----------------------------------+-------------------+---------+------+-------+----------+-------------+
添加解釋結果。 –
你嘗試過'和dateStartCol BETWEEN'2012-08-01' AND'2012-08-31''。不知道它是否會有所幫助,但值得一試。 – Bojangles
我已經嘗試了BETWEEN,並且在時間上沒有顯着差異(從0.29到0.28)。 -還是)感謝你的建議。 – mh1