Index all columns

Question

Knowing that an indexed column leads to a better performance, is it worthy to indexes all columns in all tables of the database? What are the advantages/disadvantages of such ap

Answer 1

• Every index requires additional CPU time and disk I/O overhead during inserts and deletions.
• Indies on non-primary keys might have to be hanged on updates, although an index on the primary key might not (this is beause updates typially do not modify the primary-key attributes).
• Each extra index requires additional storage spae.
• For queries whih involve onditions on several searh keys, e ieny might not be bad even if only some of the keys have indies on them. Therefore, database performane is improved less by adding indies when many indies already exist.