maria-discuss team mailing list archive

["Reinis Rozitis" <r@xxxxxxx>]

> MariaDB 10.0.25 - 13 rows in set (1.67 sec)
> MariaDB 10.0.31 - 13 rows in set (29.06 sec)
>
> +------+-------------+------------------+-------+----------------------------+---------+---------+------+------+----------------------------------------------+
> | id   | select_type | table            | type  | possible_keys 
> | key     | key_len | ref  | rows | Extra 
> |
> +------+-------------+------------------+-------+----------------------------+---------+---------+------+------+----------------------------------------------+
> |    1 | SIMPLE      | service_perf_651 | range | 
> PRIMARY,service_perf_1_idx | PRIMARY | 16      | NULL |    1 | Using 
> where; Using temporary; Using filesort |
> +------+-------------+------------------+-------+----------------------------+---------+---------+------+------+----------------------------------------------+


This is typical when the MySQL query optimiser decides that it will be 
faster to use an index for sorting rather than selecting.
Sometimes the query plans change because of versions or table/index 
statistics.


For testing purposes you can try to drop the "order by entry_time" part or 
add FORCE INDEX:

SELECT ... from service_perf_651  FORCE INDEX(service_perf_1_idx) WHERE ...

rr