What is the effect of the delayed discovery rule on cause of action?

The general rule is that a cause of action accrues when the wrongful act is done and not at the time of plaintiff's discovery. But under the delayed discovery rule, a cause of action will not accrue until the plaintiff discovers or should have discovered, through the exercise of reasonable diligence, all the facts essential to the cause of action. (Leaf v. City of San Mateo (1980) 104 Cal.App.3d 398, 407, 163 Cal.Rptr. 711.)