Enables Greenplum memory management features. The distribution algorithm eager_free takes advantage of the fact that not all operators execute at the same time (in Greenplum Database 4.2 and later). The query plan is divided into stages and Greenplum Database eagerly frees memory allocated to a previous stage at the end of that stage's execution, then allocates the eagerly freed memory to the new stage.

When set to none, memory management is the same as in Greenplum Database releases prior to 4.1.

When set to auto, query memory usage is controlled by statement_mem and resource queue memory limits.