For example, a program that takes a second or more to write a record because it has dozens of keys per record, makes perfect sense. And even if the system is called upon to search for over a million records a day, the heavy use of keys will make the overall application work better. The only way to be confident that you have properly indexed your data is to measure, measure, measure. The purpose of a path is to divide a dataset into small, manageable subsets of entries that can be retrieved, displayed, and updated easily. A path should divide a dataset into many short chains, rather than a few long chains.
Paths are never absolutely necessary.
You can accomplish the same inquiry by a serial scan of the entire dataset. The only reason for a path is to make the retrieval faster than a serial scan. However, if the number of unique search values is less than the number of entries per disc block, a serial scan will be faster than a chained retrieval.