Develop a web crawler with Python programming language that searches through at least 10 pre-determined news websites and saves the URLs, titles, author names, publication dates, and full article contents in a MySQL database. The crawler should be able to visit each website, extract the relevant data without interrupting the website's server requests, and store it in the database with a unique identifier. The crawler's performance should also be optimized to ensure speed and accuracy when extracting data.
This prompt doesn't seem malicious.