Re: Advice on indexing a datetime column

[Rick James]

Adding the datetime index will not hurt much. Such an index (assuming data is inserted in chronological order, or nearly so) will have a hot spot at the end, there for will require very little disk I/O.

"Hundreds per second" show be fine.

Consider using TIMESTAMP instead of DATETIME; the former is 4 bytes; the latter is 8. They hold equivalent information (except for timezone issues).

A GUID, on the other hand, would be running around all over the index, doing random read-modify-writes. Adding that would slow you down to disk speed.

SHOW CREATE TABLE for further discussion.