NonStop SQL/MP Reference Manual

NonStop SQL/MP Reference Manual—142115
E-21
Considerations—EXPLAIN
Sort cost
Indicates the relative cost of the sort operation. Lower numbers
indicate more efficient and less costly execution.
Sort key columns
Identifies columns used in the sort by column names qualified
by correlation or table names or (if the sort column is an
expression) by position in the select list. Also lists collations
associated with the sort columns.
Sort rows in the
Specifies whether the rows sorted are from the result of a
SELECT statement or a union of SELECT statements, on the
current table, or on a composite table.
Sort technique
Describes the sort technique: FastSort or insertion into a key-
sequenced file.
Sort type
Describes the type of sort: insertion into an entry-sequenced
disk file, parallel sorting, parallel sort/merge, Sortmerge, or
User Process Sort.
SQL request
Specifies the type of statement that is the subject of the plan:
DELETE INSERT-SELECT
UPDATE UNION of SELECT
SELECT UNION of INSERT-SELECTs
INSERT
Table
Specifies the fully qualified Guardian name of the table. For
scan or join operations, the name represents the table being
accessed; for an INSERT operation, the name represents the
table to receive the inserted data.
Table selectivity
The percentage of the table that is reflected in the result.