67.6. Limitations
GIN
assumes that indexable operators are strict. This
means that
extractValue
will not be called at all on a null
item value (instead, a placeholder index entry is created automatically),
and
extractQuery
will not be called on a null query
value either (instead, the query is presumed to be unsatisfiable). Note
however that null key values contained within a non-null composite item
or query value are supported.