Here is a nice tip when you would like to speed up your database query for a given page. When you make a query for certain specific data in WordPress, WordPress by default will return ALL the data in an object. 95% of the time it is not required to return all the data from the database. It will just make your page loading slow especially if you have a WordPress Database that has taken on some fat. What you want WordPress to do is to STOP when it found the number of sufficient data/rows and not run around like a headless chicken on a black Friday sale collecting everything it possibly can.

Inside the WP_Query CLASS, class-wp-query.php(line 684) there exist a argument to assit with this:

@type bool $no_found_rows Whether to skip counting the total rows found. Enabling can improve performance. Default false.

Extraction from the code inside the class-wp-query.php where it test to see if the option was set when the query was passed.:

Basically what it does is to NOT return all the rows. For example, if I only want to display 4x products in a certain category.

Very basic WordPress WP_Query request.:

Another example used in a loop in the Twenty Seventy Theme to only return 3x posts.: