Calculate database index cardinality and selectivity. Selectivity = distinct values / total rows. Indexes are beneficial above 5-10% selectivity; below that, full scans are faster.
Enter the values for the scenario you are assessing. Calculate database index cardinality and selectivity. Selectivity = distinct values / total rows. Indexes are beneficial above 5-10% selectivity; below that, full scans are faster. Use the index cardinality result to inform your calculation.