Query Tuning / Planner Method Configuration v13
This section describes the configuration parameters used for planner method configuration.
edb_enable_pruning
Parameter Type: Boolean
Default Value: true
Range: {true | false}
Minimum Scope of Effect: Per session
When Value Changes Take Effect: Immediate
Required Authorization to Activate: Session user
When set to TRUE
, edb_enable_pruning
allows the query planner to early-prune partitioned tables. Early-pruning
means that the query planner can prune
(i.e., ignore) partitions that would not be searched in a query before
generating query plans. This helps improve performance time as it eliminates the generation of query plans of partitions that would not be searched.
Conversely, late-pruning
means that the query planner prunes partitions after
generating query plans for each partition. (The constraint_exclusion
configuration parameter controls late-pruning.)
The ability to early-prune depends upon the nature of the query in the WHERE
clause. Early-pruning can be utilized in only simple queries with constraints of the type WHERE column = literal
(e.g., WHERE deptno = 10)
.
Early-pruning is not used for more complex queries such as WHERE column = expression
(e.g., WHERE deptno = 10 + 5)
.
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- edb_enable_pruning