This parameter specifies the number of pages in each of the extended memory segments in the database. There are platform-dependent considerations when setting this configuration parameter.
Recommendation: This parameter only has an effect when extended storage is available, and is used as shown by the num_estore_segs parameter. When specifying the number of pages to be used in each extended memory segment, you should also consider the number of extended memory segments by reviewing and modifying the num_estore_segs parameter.