Several users post in my blog and I want to avoid duplicated content. The only way to check automatically if a post is equal to another is to keep an URL each post must have in a database (this URL points to the place where the base information is placed).
So, I thought that the easier was to create a WP plugin that checks if there is another URL equal in the database to warn the author.
The question is: it will be very agressive against PHP to store hundreds (or thousands) of URL addresses in an array? I prefer to keep these in an array better than in a MySQL database because it's simpler, but if it's necessary I will write the code to access to the DB.