I have been customizing wordpress, I stuck around the problem for Limiting Number Of Posts per page. After digging into the code I found the tables wp_options which allows setting of wordpress.
This table has columns option_name and option_value. I change the option_value for the post_per_page to number of want to limit my post.
You can see the details for this row by running query below
WHERE option_name = ‘posts_per_page’
LIMIT 0 , 30