EXPLAIN - Incremental Sort

Description:

Takes partially sorted data from a child node and produces output sorted according to a more specific sort key, using either memory if available (depending on the work_mem setting) or “spilling” to disk. This can be used if the input can be scanned in a partially-sorted manner—e.g., if scanning a btree index compatible with the desired sort order.

Important Fields:

• Sort Key
• Presorted Key
• Pre-sorted Groups
• Full-sort Groups