Query Tuning Configuration Parameters in Greenplum
The following parameters control the types of plan operations the query planner has to choose from. Enabling or disabling certain plan operations is a way to force the planner to choose a different plan. These can be useful in testing a query using different plan types to see which plan offers the best performance.
Query Planner Costing Parameters
Warning: Greenplum recommends that you do not adjust these query costing parameters. They have already been tuned to reflect Greenplum Database hardware configurations and typical workloads. All of these parameters are related. Changing one without changing the others can have adverse affects on performance.