Output Old Value On Update Option of Dynamic Lookup in Informatica

Here is some important properties of Dynamic Lookup Transformation

Dynamic Lookup Cache	Flat File	Indicates to use a dynamic lookup cache. Inserts or updates rows in the lookup cache as it passes rows to the target table.
	Pipeline	Use with the lookup cache enabled.
	Relational
Output Old Value On Update	Flat File	Use with dynamic caching enabled. When you enable this property, the Integration Service outputs old values out of the lookup/output ports. When the Integration Service updates a row in the cache, it outputs the value that existed in the lookup cache before it updated the row based on the input data. When the Integration Service inserts a row in the cache, it outputs null values.
	Pipeline	When you disable this property, the Integration Service outputs the same values out of the lookup/output and input/output ports.
	Relational	This property is enabled by default.

Note: 

In order to achieve the SCD type 2 with Dynamic Cache in informatica ,enable Output Old Value On Update in  Dynamic Lookup else it will inconsistent state .