dhmax Routine--Create Default Maximum Histogram Value

Object Management Extension User Guide > Object Management Extension User Guide > Defining Data Types > dhmax Routine--Create Default Maximum Histogram Value

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This routine creates the default maximum histogram value. The default histogram values are used by the optimizer when no histogram data is present in the system catalogs. For a discussion of creating a default histogram routine, see dhmin Routine. If the II_DT_NOHISTOGRAM attribute is set, then this routine is not necessary.

This routine and the hmax routine form a pair, similar to the pair hmin and dhmin, except that hmax and dhmax deal with the maximum and default maximums, respectively, instead of the minimums.

Place the address of this routine in the dtd_dhmax_addr field of the IIADD_DT_DFN structure.

Inputs

The inputs for this function are:

scb

Pointer to an SCB

dv_from

Pointer to a datavalue containing the type for the value

dv_histogram

Pointer to a datavalue for the histogram

Outputs

The outputs for this function are:

*(dv_histogram-db_data)

Filled with the histogram value

Returns

II_STATUS

Last modified date: 11/28/2023