This illustration shows a Oracle9i server with Oracle Text and Oracle Ultra Search. It illustrates the following steps in queuing URLs:

1. Oracle spawns a crawler according to schedule.
2. The crawler initiates multiple crawling threads.
3. The crawler thread removes the next URL in the queue.
4. A crawler thread fetches the URL page from the Web.
5. A crawler thread extracts the hypertext links from the URL page and inserts new links into the URL queue.