Need some help with select datetime range performance

MySQL & MariaDB Other MySQL® Questions
1

I have a db at work a colleague created. I don’t have the ability to change the schema, but I could make a case for it if there is an opportunity for some speed improvements.

The app I have has some results in it that have dates. So when I get the results I do a select that looks something like this:

select time, text from results
where
results.error_level_id = 100 and
results.log_source_id = 200 and
time >= ‘2008-08-13 15:00’ and
time <= ‘2008-08-14 15:00’

I wouldn’t think that it would but this query takes about 136s according to the MySQL query browser. Even when the result is an empty set.

So I have a few questions:

Why does it take so long?
How can I make it faster?

Thanks in advance!

2

I recommend gathering the following information:

  1. The EXPLAIN plan for your query
  2. SHOW TABLE STATUS LIKE ‘results’
  3. SHOW INDEXES FROM results

After that, someone here might have a suggestion.