mysql 7 +加入桌面，如何加速？

Question

我有7个表格。表1是“父表”和表2-7的关系。

我想进行一次查询，获取表1的行，以及表2-7中的id列表。我已经尝试了下面的查询，但对于大型数据库，我的查询需要15秒。我想知道如何让这个查询更快？

编辑有两点要注意： - >删除几个不同的不仅节省了4秒钟，然后我仍然得到10-11秒

查询

- >删除1从连接表（并不重要）该查询将时间从15秒减少到2-3秒。删除2个连接表（再次无关紧要）将查询减少到1/2秒。

SELECT 
    table1.table1_id as table1Id, 
    GROUP_CONCAT(DISTINCT table2.table2_id) AS table2Ids, 
    GROUP_CONCAT(DISTINCT table3.table3_id) AS table3Ids, 
    GROUP_CONCAT(DISTINCT table4.table4_id) AS table4Ids, 
    GROUP_CONCAT(DISTINCT table5.table5_id) AS table5Ids, 
    GROUP_CONCAT(DISTINCT table6.table6_id) AS table6Ids, 
    GROUP_CONCAT(DISTINCT table7.table7_id) AS table7Ids 
    FROM table1 
    LEFT JOIN table2 ON table1.table1_id = table2.table1_id 
    LEFT JOIN table3 ON table1.table1_id = table3.table1_id 
    LEFT JOIN table4 ON table1.table1_id = table4.table1_id 
    LEFT JOIN table5 ON table1.table1_id = table5.table1_id 
    LEFT JOIN table6 ON table1.table1_id = table6.table1_id 
    LEFT JOIN table7 ON table1.table1_id = table7.table1_id 
    WHERE table1.archived = false 
    GROUP BY table1.table1_id LIMIT 1000 

我解释查询：

+----+-------------+------------------+------------+-------+----------------------------------------------------------------------------------------------------+---------------------------+---------+--------------------------+------+----------+-------------+ 
| id | select_type | table   | partitions | type | possible_keys                      | key      | key_len | ref      | rows | filtered | Extra  | 
+----+-------------+------------------+------------+-------+----------------------------------------------------------------------------------------------------+---------------------------+---------+--------------------------+------+----------+-------------+ 
| 1 | SIMPLE  | table1   | NULL  | index | PRIMARY,unique_name_in_table8, table8_idx,table9_idx,table10_idx         | PRIMARY     | 4  | NULL      | 1 | 10.00 | Using where | 
| 1 | SIMPLE  | table2   | NULL  | ref | PRIMARY                       | PRIMARY     | 4  | db.table1.table1_id  | 20 | 100.00 | Using index | 
| 1 | SIMPLE  | table3   | NULL  | ref | table3_to_table1_id_idx                   | table3_to_table1_id_idx | 4  | db.table1.table1_id  | 824 | 100.00 | Using index | 
| 1 | SIMPLE  | table4   | NULL  | ref | table4_word_unique,table4_to_table1_id_idx               | table4_to_table1_id_idx | 4  | db.table1.table1_id  | 4 | 100.00 | Using index | 
| 1 | SIMPLE  | table5   | NULL  | ref | table5_to_table1_id_idx                   | table5_to_table1_id_idx | 4  | db.table1.table1_id  | 26 | 100.00 | Using index | 
| 1 | SIMPLE  | table6   | NULL  | ref | table6_to_table1_id_idx                   | table6_to_table1_id_idx | 4  | db.table1.table1_id  | 3 | 100.00 | Using index | 
| 1 | SIMPLE  | table7   | NULL  | ref | table7_to_table1_id_idx                   | table7_to_table1_id_idx | 4  | db.table1.table1_id  | 483 | 100.00 | Using index | 
+----+-------------+------------------+------------+-------+----------------------------------------------------------------------------------------------------+---------------------------+---------+--------------------------+------+----------+-------------+ 

Answer 1

我试图重写查询。试着让我知道。我没有测试过它。

SELECT 
    t1.table1Id, 
    GROUP_CONCAT(DISTINCT table2.table2_id) AS table2Ids, 
    GROUP_CONCAT(DISTINCT table3.table3_id) AS table3Ids, 
    GROUP_CONCAT(DISTINCT table4.table4_id) AS table4Ids, 
    GROUP_CONCAT(DISTINCT table5.table5_id) AS table5Ids, 
    GROUP_CONCAT(DISTINCT table6.table6_id) AS table6Ids, 
    GROUP_CONCAT(DISTINCT table7.table7_id) AS table7Ids 
FROM (
    SELECT table1_id as table1Id 
    FROM table1 
    WHERE table1.archived = false 
    GROUP BY table1.table1_id LIMIT 1000 
    ) AS t1 
    INNER JOIN table2 ON t1.table1Id = table2.table1_id 
    INNER JOIN table3 ON t1.table1Id = table3.table1_id 
    INNER JOIN table4 ON t1.table1Id = table4.table1_id 
    INNER JOIN table5 ON t1.table1Id = table5.table1_id 
    INNER JOIN table6 ON t1.table1Id = table6.table1_id 
    INNER JOIN table7 ON t1.table1Id = table7.table1_id 

Answer 2

的解释说，table2不会对table1Id的索引。

尝试：

create index table2_to_table1_id_idx on table2(table1Id); 

这可能会提高性能足够了，但对于这个特定的查询创建覆盖索引，以最大限度地提高性能：

create index table2_table1_id_idx on table2(table1Id, table2Id); 
create index table3_table1_id_idx on table3(table1Id, table3Id); 
create index table4_table1_id_idx on table4(table1Id, table4Id); 
create index table5_table1_id_idx on table5(table1Id, table5Id); 
create index table6_table1_id_idx on table6(table1Id, table6Id); 
create index table7_table1_id_idx on table7(table1Id, table7Id); 

有了这些指标意味着你能避免击中基表完全。