Choosing EXPLAIN and tuning options
In the Select tuning activities to run window, you can configure the default set of EXPLAIN and tuning options.
Define the tuning task name and description.
EXPLAIN options
Expand this section to set values for Db2 special registers (EXPLAIN options), used by Db2 to create an access plan.
To check the actual execution
values, select the checkbox Collect actual execution values to use in access plan tools,
if the statement is a SELECT statement
A special register is a storage area that is defined
for an application process by the database manager. It is used to store information that can be
referenced in SQL statements. A reference to a special register is a reference to a value provided
by the current server. Attention: The SQL statement runs
only one time during the tuning task.
Refer to the Special registers topic for detailed description of each special register.
Tuning options
Click the checkbox to the left of each tuning option that you want to implement.
- Format and annotate the statement
- Generate access plan graph
- Recommend RUNSTATS commands
- Recommend new indexes