Этот урок пока на английском.
Why is this query slow?
A query that takes 2 ms on a thousand rows can take 2 seconds on ten million. Indexes fix that, and EXPLAIN shows you whether they are actually being used.
Этот урок пока на английском.
A query that takes 2 ms on a thousand rows can take 2 seconds on ten million. Indexes fix that, and EXPLAIN shows you whether they are actually being used.