Neoview Query Guide (R2.2)

3 Query Plan Operators
Use the information in this section to understand the fields (called tokens) in the DESCRIPTION
column when you use the EXPLAIN statement and Visual Query Planner to review and
understand query execution plans. For information about the EXPLAIN statement, see the Neoview
SQL Reference Manual. For information about using Visual Query Planner to analyze plans, see
Chapter 2 (page 19).
This section provides information about:
“Operators and Description Fields” (page 32)
“Understanding Joins” (page 36)
“Nested Joins” (page 37)
“Merge Joins” (page 40)
“Hybrid Hash Joins” (page 41)
“Ordered Joins” (page 44)
“Insert Operators” (page 47)
“Update Operators” (page 48)
“Delete Operators” (page 50)
“Scan Operators” (page 53)
“Groupby and Sort Operators” (page 56)
“Union Operators” (page 61)
“Miscellaneous Operators” (page 62)
“Operators Appearing Infrequently or Not At All” (page 64)
The operators listed here commonly appear in Neoview query execution plans:
“CURSOR_DELETE Operator” (page 50)
“CURSOR_UPDATE Operator” (page 48)
“ESP_EXCHANGE Operator” (page 34)
“FILE_SCAN Operator” (page 53)
“FILE_SCAN_UNIQUE Operator” (page 54)
“FIRSTN Operator” (page 62)
“HASH_GROUPBY Operator” (page 56)
“HASH_PARTIAL_GROUPBY_LEAF Operator” (page 57)
“HASH_PARTIAL_GROUPBY_ROOT Operator” (page 57)
“HYBRID_HASH_ANTI_SEMI_JOIN Operator” (page 43)
“HYBRID_HASH_JOIN Operator” (page 42)
“HYBRID_HASH_SEMI_JOIN Operator” (page 42)
“INDEX_SCAN Operator” (page 54)
“INDEX_SCAN_UNIQUE Operator” (page 55)
“INSERT Operator” (page 47)
“INSERT_VSBB Operator” (page 47)
“LEFT_HYBRID_HASH_JOIN Operator” (page 43)
“LEFT_MERGE_JOIN Operator” (page 41)
“LEFT_NESTED_JOIN Operator” (page 38)
“LEFT_ORDERED_HASH_JOIN Operator” (page 46)
“MERGE_ANTI_SEMI_JOIN Operator” (page 41)
“MERGE_JOIN Operator” (page 40)
“MERGE_SEMI_JOIN Operator” (page 40)
“MERGE_UNION Operator” (page 61)
31