The documentation on the MySQL seems lacking in this area.
If you had a table where you typically select everything a “page” at a time using LIMIT x, y and ORDERing BY a column, is it worth adding an index to the ORDER BY column?
Let's say you had a simple table with 100k records:
id, name, html
And you're doing queries like:
SELECT * FROM table ORDER BY name LIMIT 50000, 50;
Can you optimise this or will it always use filesort?