Re: MySQL query with timestamp not using index

[Rick James]

Instead of DESCRIBE, show us SHOW CREATE TABLE, it is more descriptive. In particular, I need to know which ENGINE it is and how the index(es) are declared. (There may be other clues.)

Please provide EXPLAIN PARTITIONS SELECT ... for each SELECT.

How many partitions and rows are in the entire table? In the last 6 days (the selected range)?

Drop "DISTINCT" -- it is unnecessary (even wrong?) when you have that GROUP BY.

It may have done PARTITION PRUNING, but punted on using the INDEX. The above infomation will help me elaborate.