A newer version of this documentation is available. Click here to view the most up-to-date release of the Greenplum 4.x documentation.


Sets the planner's assumption about the effective size of the disk cache that is available to a single query. This is factored into estimates of the cost of using an index; a higher value makes it more likely index scans will be used, a lower value makes it more likely sequential scans will be used. This parameter has no effect on the size of shared memory allocated by a Greenplum server instance, nor does it reserve kernel disk cache; it is used only for estimation purposes.

Value Range Default Set Classifications
floating point 512MB master