Enum SparseStrategy

enum SparseStrategy {
    Gather,
    MaskAllFieldsWithNullsSkipOne,
    MaskSkipWithoutNulls,
    MaskSkipFullyNull,
}

How to compute the logical nulls of a sparse union. All strategies return the same result. Those starting with Mask perform bitwise masking for each chunk of 64 values, including computing expensive selection masks of fields: which fields masks must be computed is the difference between them

Variants

Gather

Gather individual bits from the null buffer of the selected field

MaskAllFieldsWithNullsSkipOne

All fields contains nulls, so we can skip the selection mask computation of one field by negating the others

MaskSkipWithoutNulls

Skip the selection mask computation of the fields without nulls

MaskSkipFullyNull

Skip the selection mask computation of the fully nulls fields