This
operation subdivides geographically large areas such as the state of
Amazonas, ensuring that they do not have more than a given number of
vertices. The idea is to speed up spatial operations like Contains,
Intersection, etc.
Here is an example of some large objects (red lines) and the number of vertices and memory used to hold them.
Compare the original number of vertices/memory with the partial list of polygons generated by the Subdivision (red line) of 'Am' state. In this example the number of vertices is up to 255 and the memory is much smaller.
See also the Advanced Dissolve operation in the vector processing menu. It may be useful to dissolve the artificial polygons of each state after some space operation.
It is accessed through:
Processing > Vector Processing > Subdivide Geometries...