OPTIMIZER_SECURE_VIEW_MERGING：OPTIMIZER_SECURE_VIEW_MERGING allows you to enable or disable view merging globally for the database. Values: FALSE - Oracle does not use view merging or predicate move-around. TRUE - Oracle assesses the query, considering all transformations, and chooses the method with the lowest cost. To take advantage of query rewrite for a particular query, you must disable the OPTIMIZER_SECURE_VIEW_MERGING parameter. Parameter type: String Syntax: OPTIMIZER_SECURE_VIEW_MERGING = {false | true | force} Default value: true Modifiable: ALTER SYSTEM Real Application Clusters: Multiple instances can have different values OPTIMIZER_PERCENT_PARALLEL Determines the level of parallelism that the optimizer will use in its costing calculations. If you set the value to 100, the optimizer will use an object's degree of parallelism when computing the cost of a full table scan. Simply put, low values will use indexes, and high values will make more use of the parallel query option in preference. We recommend that you use the default setting for OLTP applications and set it to 100 for decision support applications, where you have multiple processors and would like to make use of the parallel query option. Note that the cost-based optimizer will always be used for an object that has a nonzero degree of parallelism. Obsolete in 9i. Default Value: 100 Values: 0 to 100 Dependencies: None
错误码
错误描述：OPTIMIZER_SECURE_VIEW_MERGING allows you to enable or disable view merging globally for the database.
Values:
FALSE - Oracle does not use view merging or predicate move-around.
TRUE - Oracle assesses the query, considering all transformations, and chooses the method with the lowest cost.
To take advantage of query rewrite for a particular query, you must disable the OPTIMIZER_SECURE_VIEW_MERGING parameter.
Parameter type: String
Syntax: OPTIMIZER_SECURE_VIEW_MERGING = {false | true | force}
Default value: true
Modifiable: ALTER SYSTEM
Real Application Clusters:
Multiple instances can have different values
OPTIMIZER_PERCENT_PARALLEL
Determines the level of parallelism that the optimizer will use in its costing calculations. If you set the value to 100, the optimizer will use an object's degree of parallelism when computing the cost of a full table scan. Simply put, low values will use indexes, and high values will make more use of the parallel query option in preference. We recommend that you use the default setting for OLTP applications and set it to 100 for decision support applications, where you have multiple processors and would like to make use of the parallel query option. Note that the cost-based optimizer will always be used for an object that has a nonzero degree of parallelism. Obsolete in 9i.
Default Value: 100
Values: 0 to 100
Dependencies: None
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