How does Greenplum ensure data consistency during backups?

In PostGIS, the ___ function is commonly used to return the spatial area of a polygon geometry.

The ___ utility in Greenplum allows administrators to recover a failed primary segment using its corresponding mirror.

Which spatial function can be used to check whether two geometries share any portion of space?

You are investigating a query with performance issues. The query joins a large orders table and a small customer table, but the execution plan shows a Redistribute motion. What should you do to optimize this query?