此查询出现在我在 mysql 系统上的慢速日志中,
# Query_time: 37 Lock_time: 0 Rows_sent: 5 Rows_examined: 405199
select euroapps.id, euroapps.name, euroapps.imageurl, euroapps.created,
application_price.retail_price, euroapps.count FROM application_price INNER JOIN
euroapps ON euroapps.id = application_price.application_id WHERE
application_price.storefront_id = '143441' AND application_price.retail_price <= 0
ORDER BY created DESC LIMIT 5;
您看到它检查了 405,199 行,这可能是查询时间长的原因吗?
类似的查询从未出现在我的慢日志中,该查询是:
select euroapps.id, euroapps.name, euroapps.imageurl, euroapps.created,
application_price.retail_price, euroapps.count FROM application_price INNER JOIN
euroapps ON euroapps.id = application_price.application_id WHERE
application_price.storefront_id = '$store' AND application_price.retail_price > 0
ORDER BY created DESC LIMIT 5
这是解释的输出:
mysql> explain select euroapps.id, euroapps.name, euroapps.imageurl, euroapps.created, application_price.retail_price, euroapps.count FROM application_price INNER JOIN euroapps ON euroapps.id = application_price.application_id WHERE application_price.storefront_id = '143441' AND application_price.retail_price <= 0 ORDER BY created DESC LIMIT 5;
+----+-------------+-------------------+--------+----------------------------------+--------------------------+---------+---------------------------------------------+--------+-----------------------------------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------------------+--------+----------------------------------+--------------------------+---------+---------------------------------------------+--------+-----------------------------------------------------------+
| 1 | SIMPLE | application_price | range | PRIMARY,idx_storedfront_price_id | idx_storedfront_price_id | 9 | NULL | 110491 | Using where; Using index; Using temporary; Using filesort |
| 1 | SIMPLE | euroapps | eq_ref | PRIMARY | PRIMARY | 4 | itunesapps.application_price.application_id | 1 | |
+----+-------------+-------------------+--------+----------------------------------+--------------------------+---------+---------------------------------------------+--------+-----------------------------------------------------------+
2 rows in set (0.00 sec)