The
SET CURRENT DEGREE statement assigns a value to the CURRENT DEGREE
special register.
This statement is not under transaction control.
Invocation
This statement can be embedded
in an application program or issued through the use of dynamic SQL
statements. It is an executable statement that can be dynamically
prepared.
Authorization
None required.
Syntax
.-=-.
>>-SET--CURRENT--DEGREE--+---+--+-string-constant-+------------><
'-host-variable---'
Description
The value of CURRENT DEGREE
is replaced by the value of the string constant or host variable.
The value must be a character string that is not longer than 5 bytes.
The value must be the character string representation of an integer
between 1 and 32 767 inclusive or 'ANY'.
If the value
of CURRENT DEGREE represented as an integer is 1 when an SQL statement
is dynamically prepared, the execution of that statement will not
use intrapartition parallelism.
If the value of CURRENT DEGREE
is a number when an SQL statement is dynamically prepared, the execution
of that statement can involve intrapartition parallelism with the
specified degree.
If the value of CURRENT DEGREE is 'ANY' when
an SQL statement is dynamically prepared, the execution of that statement
can involve intrapartition parallelism using a degree determined by
the database manager.
- host-variable
- The host-variable must be of data type
CHAR or VARCHAR and the length must not exceed 5. If a longer field
is provided, an error will be returned (SQLSTATE 42815). If the actual
value provided is larger than the replacement value specified, the
input must be padded on the right with blanks. Leading blanks are
not allowed (SQLSTATE 42815). All input values are treated as being
case-insensitive. If a host-variable has
an associated indicator variable, the value of that indicator variable
must not indicate a null value (SQLSTATE 42815).
- string-constant
- The string-constant length must not
exceed 5.
Notes
- The degree of intrapartition parallelism for static SQL statements
can be controlled using the DEGREE option of the PREP or BIND command.
- The actual runtime degree of intrapartition parallelism will be
the lower of:
- Maximum query degree (max_querydegree) configuration
parameter
- Application runtime degree
- SQL statement compilation degree
- The intra_parallel database manager configuration
parameter must be on to use intrapartition parallelism. If it is set
to off, the value of this register will be ignored and the statement
will not use intrapartition parallelism for the purpose of optimization
(SQLSTATE 01623).
- The value in the CURRENT DEGREE special
register and the intra_parallel setting can be
overridden in a workload by setting the MAXIMUM DEGREE workload attribute.
- Some SQL statements cannot use intrapartition parallelism.