Question

我有此查询，需要花一些时间（大约10分钟）。

SELECT COUNT(DISTINCT(column)) var, 
       column2 var2 
FROM table 
WHERE column<>'X' and 
      column2 between 'Y' and 'Z' 
GROUP BY var2 
ORDER BY var DESC

任何想法如何优化速度？我尝试使用索引，但仍然很慢。也许它们设置不正确。 Y和Z是时间戳（如果重要），而X是此查询根本不需要的东西，但在表中，因为同一应用程序的其他查询都需要X。该表非常大-数百万行，并且尚未增长。

编辑：以下是示例的解释结果：

    mysql> EXPLAIN SELECT COUNT(DISTINCT(ip)) v, geo n from idevaff_iptracking where geo<>'XX' and stamp between '1525122000' and '1543615199' group by n order by v desc;
+------+-------------+--------------------+-------+------------------------+--------------+---------+------+---------+-----------------------------------------------------------+
| id   | select_type | table              | type  | possible_keys          | key          | key_len | ref  | rows    | Extra                                                     |
+------+-------------+--------------------+-------+------------------------+--------------+---------+------+---------+-----------------------------------------------------------+
|    1 | SIMPLE      | idevaff_iptracking | range | stamp,geo,geo_stamp_ip | geo_stamp_ip | 9       | NULL | 3469323 | Using where; Using index; Using temporary; Using filesort |
+------+-------------+--------------------+-------+------------------------+--------------+---------+------+---------+-----------------------------------------------------------+
1 row in set (0.00 sec)

表中的表格如下：

id，acct_id，ip，refer，stamp，hit_time，hit_date，src1，src2，split，sub_id，tid1，tid2，tid3，tid4，target_url，geo。

索引如下：

    mysql> SHOW INDEX FROM idevaff_iptracking
    -> ;
+--------------------+------------+--------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table              | Non_unique | Key_name           | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+--------------------+------------+--------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| idevaff_iptracking |          0 | PRIMARY            |            1 | id          | A         |     6775984 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_ip         |            1 | acct_id     | A         |           2 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_ip         |            2 | ip          | A         |     6775984 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | ip                 |            1 | ip          | A         |     6775984 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | stamp              |            1 | stamp       | A         |     6775984 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id            |            1 | acct_id     | A         |           4 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | geo                |            1 | geo         | A         |         440 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | tid1               |            1 | tid1        | A         |         276 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | tid2               |            1 | tid2        | A         |         514 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | tid3               |            1 | tid3        | A         |          34 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | tid4               |            1 | tid4        | A         |        5623 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_stamp_ip   |            1 | acct_id     | A         |         744 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_stamp_ip   |            2 | stamp       | A         |     6775984 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_stamp_ip   |            3 | ip          | A         |     6775984 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | geo_stamp_ip       |            1 | geo         | A         |       22362 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | geo_stamp_ip       |            2 | stamp       | A         |     6775984 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | geo_stamp_ip       |            3 | ip          | A         |     6775984 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid1_stamp |            1 | acct_id     | A         |         658 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid1_stamp |            2 | tid1        | A         |       11866 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid1_stamp |            3 | stamp       | A         |     6775984 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid2_stamp |            1 | acct_id     | A         |           2 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid2_stamp |            2 | tid2        | A         |       18666 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid2_stamp |            3 | stamp       | A         |     6775984 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid3_stamp |            1 | acct_id     | A         |           2 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid3_stamp |            2 | tid3        | A         |        1832 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid3_stamp |            3 | stamp       | A         |     6775984 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid4_stamp |            1 | acct_id     | A         |           2 |     NULL | NULL   |      | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid4_stamp |            2 | tid4        | A         |        5060 |     NULL | NULL   | YES  | BTREE      |         |               |
| idevaff_iptracking |          1 | acct_id_tid4_stamp |            3 | stamp       | A         |     6775984 |     NULL | NULL   |      | BTREE      |         |               |
+--------------------+------------+--------------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
29 rows in set (0.00 sec)

Answer 1

添加此综合索引：

INDEX(column2, column)

如果这还不够，我们需要查看SHOW CREATE TABLE以便进行进一步讨论。（geo_stamp_ip不好。）

跨列展开数组（tid's）通常是一个错误。

EXPLAIN FORMAT=JSON
SELECT  COUNT(DISTINCT ip) v, geo n
    from  idevaff_iptracking
    where  geo<>'XX'
      and  stamp between '1525122000' AND '1543615199'
    group by  n
    order by  v desc;

某些索引是多余的。通常，如果您有INDEX(a)，则可以删除INDEX(a,b)。（例如：acct_id_ip）

从表WHERE col <>'X'和col2在'Y'和'Z'之间优化SELECT COUNT（DISTINCT（col））var，col2 var2 GROUP BY var2 ORDER BY VAR DESC;为了速度？

1 个答案: