Discuss the special performance challenges posed by very large databases. Be sure to address specific performance analysis which should be undertaken, and the most critical areas for performance tuning, and other areas that deserve scrutiny (e.g., frequently run queries). Explain what steps may be taken with respect to the data model, physical storage, indices, data architecture, memory and resource management, etc., in order to optimize performance. What other operational aspects must be considered when working with very large databases (e.g., operations that batch-load a lot of data; inserting and deleting of data; and archiving or deleting data that no longer needs to reside in the main database)?