The error notices are raised by some shady search bots who do not identify themselves as browsers. They are harmless and cannot bi triggered or seen by normal users. We will add however some checks to prevent these errors from showing in the error log (for the next Shoppica update).

The database queries depend on the categories you have in the menu. Opencart has lower count queries because it displays only two levels deep. Shoppica displays the entire category tree. Every category makes one additional query to determine the SEO url. This query is ‘cheap’ however as it is very simple.

Shoppica 2 we have reduced the additional queries greatly, so you can try. The major opencart performance problem is the products count in category menu and it has nothing to do with Shoppica. In general, Shoppica 2 provides very much the same performance as the default opencart theme, so you can safely use it.

However, we have prepared a special Shoppica plugin – SmartCache, which we will release for free in the next week. With this plugin we achieved 200% better performance than opencart.