Hi. My hosting provider recommended me to optimize my 200,000 record table in order to save resources.
I do _always_ this query: SELECT * FROM books WHERE isbn='foo' LIMIT 1 The primary key of this table was 'id', and 'isbn' was and INDEX field. I've modified this: ALTER TABLE books DROP PRIMARY KEY, ADD INDEX ('isbn') ALTER TABLE books ADD PRIMARY KEY ('isbn') Is this a good change? Am I going to waste less resources with 'isbn' field as primary key? Thank you very much.