The Access Path Advisor uses EXPLAIN information to evaluate the access path selected by the optimizer. The advisor then warns you if certain suboptimal types of access are selected to process the query. By understanding which types of access are suboptimal, you can look for ways to rewrite the query to avoid those operations. You can also use the Access Path Advisor warnings to get hints about where to look for problems in the access plan graph for the query. You might also do further research about the types of access that are mentioned in the explanations by searching the technical information for the database that you are working with.