Choosing appropriate bind options

The following bind options can affect the optimization of your queries:

Query optimization class

A query optimization class implies that the optimizer can use a specified set of optimization techniques and query rewrite rules when compiling a statement.

For dynamic SQL, the query optimization class is not inherited from the originating package. Instead, the value of the CURRENT QUERY OPTIMIZATION special register is used.

For more information, see the section on adjusting the optimization class in the Administration Guide.

Isolation level

The isolation level affects not only the degree of isolation among applications but also the performance characteristics of an individual application. This is because the CPU and memory resources that are required to obtain and free locks vary with the isolation level.

Dynamic SQL inherits the isolation level from the originating package.

For more information, see the section on concurrency in the Administration Guide.

Blocking

Cursor blocking is a technique that reduces database manager overhead by retrieving rows or a block of data for a single operation. When all the rows in a block have been processed, another block of rows is retrieved.

Dynamic SQL inherits cursor blocking from the originating package.

For more information, see the section on cursor blocking in the Administration Guide.

Degree

The degree of CPU or intra-partition parallelism implies that the optimizer can use a specified set of degree techniques and query rewrite rules when compiling a statement.

For dynamic SQL, the degree of parallelism is not inherited from the originating package. Instead, the value of the CURRENT DEGREE special register is used.

For more information, see the section on adjusting the degree of parallelism in the Administration Guide.