Functions
double	NumDistinctValues (THD *thd, const Field &field)
	If secondary engine is available, return number of distinct values (NDV) information for specified field. More...

Function Documentation

◆ NumDistinctValues()

double secondary_statistics::NumDistinctValues	(	THD *	thd,
		const Field &	field
	)

If secondary engine is available, return number of distinct values (NDV) information for specified field.

Parameters

thd	The current thread.
field	The field we request NDV for

Returns: NDV if secondary engine is active and has information on column, -1.0, otherwise