Machine configuration: ali cloud ECS dual-core 4 g
The total number of records 5 w - 6 w
Query function: from all records using group by find out each site_code corresponding to the maximum m's record

 select * from hour_data where (source=0 or source=2) and (time_ticks between '21:23:33' 2017-10-01 and '2017-10-15 s 21:23:33') group by site_code order by m DESC limit 10; 

This statement is the total time of around 10 s, the result is slow? If slow from where am I supposed to change?

CodePudding user response:

Explain the execution plan, may be not appropriate indexes

CodePudding user response:

How big amount of data, large, to be built on the field index (as far as possible is to distinguish the degree of large field)