DB2 Version 9.7 for Linux, UNIX, and Windows

CREATE WORK CLASS SET statement

The CREATE WORK CLASS SET statement defines a work class set.

Invocation

This statement can be embedded in an application program or issued interactively. It is an executable statement that can be dynamically prepared only if DYNAMICRULES run behavior is in effect for the package (SQLSTATE 42509).

Authorization

The privileges held by the authorization ID of the statement must include WLMADM or DBADM authority.

Syntax


>>-CREATE WORK CLASS SET--work-class-set-name------------------->

>--+-------------------------------------+---------------------><
   |    .-,-------------------------.    |   
   |    V                           |    |   
   '-(----| work-class-definition |-+--)-'   

work-class-definition

   .-WORK CLASS-.                    
|--+------------+--work-class-name------------------------------>

>--| work-attributes |--| position-clause |---------------------|

work-attributes

|--WORK TYPE---------------------------------------------------->

>--+-READ--+------------------------+-----------------------+---|
   |       '-| for-from-to-clause |-'                       |   
   +-WRITE--+------------------------+----------------------+   
   |        '-| for-from-to-clause |-'                      |   
   +-CALL--+-------------------+----------------------------+   
   |       '-| schema-clause |-'                            |   
   +-DML--+------------------------+------------------------+   
   |      '-| for-from-to-clause |-'                        |   
   +-DDL----------------------------------------------------+   
   +-LOAD---------------------------------------------------+   
   '-ALL--+------------------------+--+-------------------+-'   
          '-| for-from-to-clause |-'  '-| schema-clause |-'     

for-from-to-clause

                                           .-TO--UNBOUNDED-.   
|--FOR--+-TIMERONCOST-+--FROM--from-value--+---------------+----|
        '-CARDINALITY-'                    '-TO--to-value--'   

schema-clause

|--ROUTINES IN SCHEMA--schema-name------------------------------|

position-clause

   .-POSITION LAST--------------------.   
|--+----------------------------------+-------------------------|
   +-POSITION BEFORE--work-class-name-+   
   +-POSITION AFTER--work-class-name--+   
   '-POSITION AT--position------------'

Description

work-class-set-name

Names the work class set. This is a one-part name. It is an SQL identifier (either ordinary or delimited). The work-class-set-name must not identify a work class set that already exists at the current server (SQLSTATE 42710). The name must not begin with the characters 'SYS' (SQLSTATE 42939).

work-class-definition

Specifies the definition of the work class.

WORK CLASS work-class-name

Names the work class. The work-class-name must not identify a work class that already exists within the work class set at the current server (SQLSTATE 42710). The work-class-name cannot begin with 'SYS' (SQLSTATE 42939).

work-attributes

The attributes of the database activity must match all of the attributes specified in this work class if that activity is to be associated with this work class.

WORK TYPE

Specifies the type of database activity.

READ

This activity includes the following statements:

All SELECT or SELECT INTO statements that do not contain a DELETE, INSERT, MERGE, or UPDATE statement, and all VALUES INTO statements
All XQuery statements

WRITE

This activity includes the following statements:

UPDATE
DELETE
INSERT
MERGE
All SELECT statements that contain a DELETE, INSERT, or UPDATE statement, and all VALUES INTO statements

CALL

Includes the CALL statement. A CALL statement is considered for a work class with a work type of CALL or ALL.

DML

Includes the statements listed under READ and WRITE.

DDL

This activity includes the following statements:

ALTER
CREATE
COMMENT
DECLARE GLOBAL TEMPORARY TABLE
DROP
FLUSH PACKAGE CACHE
GRANT
REFRESH TABLE
RENAME
REVOKE
SET INTEGRITY

LOAD

DB2® load operations.

ALL

All recognized workload management (WLM) activity that falls under any one of the keywords described above.

FOR

Indicates the type of information that is being specified in the FROM from-value TO to-value clause. The FOR clause is only used for the following work types:

READ
WRITE
DML
ALL

TIMERONCOST: The estimated cost of the work, in timerons. This value is used to determine whether the work falls within the range specified in the FROM from-value TO to-value clause.
CARDINALITY: The estimated cardinality of the work. This value is used to determine whether the work falls within the range specified in the FROM from-value TO to-value clause.

FROM from-value TO UNBOUNDED or FROM from-value TO to-value

Specifies the range of either timeron value (for estimated cost) or cardinality within which the database activity must fall if it is to be part of this work class. The range is inclusive of from-value and to-value. If this clause is not specified for the work class, all work that falls within the specified work type will be included (that is, the default is FROM 0 TO UNBOUNDED). This range is only used for the following work types:

READ
WRITE
DML
ALL

FROM from-value TO UNBOUNDED: The from-value must be zero or a positive DOUBLE value (SQLSTATE 5U019). The range has no upper bound.
FROM from-value TO to-value: The from-value must be zero or a positive DOUBLE value and the to-value must be a positive DOUBLE value. The from-value must be smaller than or equal to the to-value (SQLSTATE 5U019).

schema-clause

ROUTINES IN SCHEMA schema-name: Specifies the schema name of the procedure that the CALL statement will be calling. This clause is only used if the work type is CALL or ALL and the database activity is a CALL statement. If no value is specified, all schemas are included.

position-clause

POSITION

Specifies where this work class is to be placed within the work class set, which determines the order in which work classes are evaluated. When performing work class assignment at run time, the database manager first determines the work class set that is associated with the object, either the database or a service superclass. The first matching work class within that work class set is then selected. If this keyword is not specified, the work class is placed in the last position.

LAST: Specifies that the work class is to be placed last in the ordered list of work classes within the work class set. This is the default.
BEFORE work-class-name: Specifies that the work class is to be placed before work class work-class-name in the list. The work-class-name must identify a work class in the work class set that exists at the current server (SQLSTATE 42704).
AFTER work-class-name: Specifies that the work class is to be placed after work class work-class-name in the list. The work-class-name must identify a work class in the work class set that exists at the current server (SQLSTATE 42704).
AT position: Specifies the absolute position at which the work class is to be placed within the work class set in the ordered list of work classes. This value can be any positive integer (not zero) (SQLSTATE 42615). If position is greater than the number of existing work classes plus one, the work class is placed at the last position within the work class set.

Rules

A workload management (WLM)-exclusive SQL statement must be followed by a COMMIT or a ROLLBACK statement (SQLSTATE 5U021). WLM-exclusive SQL statements are:
- CREATE HISTOGRAM TEMPLATE, ALTER HISTOGRAM TEMPLATE, or DROP (HISTOGRAM TEMPLATE)
- CREATE SERVICE CLASS, ALTER SERVICE CLASS, or DROP (SERVICE CLASS)
- CREATE THRESHOLD, ALTER THRESHOLD, or DROP (THRESHOLD)
- CREATE WORK ACTION SET, ALTER WORK ACTION SET, or DROP (WORK ACTION SET)
- CREATE WORK CLASS SET, ALTER WORK CLASS SET, or DROP (WORK CLASS SET)
- CREATE WORKLOAD, ALTER WORKLOAD, or DROP (WORKLOAD)
- GRANT (Workload Privileges) or REVOKE (Workload Privileges)
A WLM-exclusive SQL statement cannot be issued within a global transaction (SQLSTATE 51041) such as, for example, an XA transaction.

Notes

Changes are written to the system catalog, but do not take effect until they are committed, even for the connection that issues the statement.
Only one uncommitted WLM-exclusive SQL statement at a time is allowed across all partitions. If an uncommitted WLM-exclusive SQL statement is executing, subsequent WLM-exclusive SQL statements will wait until the current WLM-exclusive SQL statement commits or rolls back.

Examples

Example 1: Create a work class set named LARGE_QUERIES that has a set of work classes representing all DML with an estimated cost greater than 9999 and an estimated cardinality greater than 1000.

   CREATE WORK CLASS SET LARGE_QUERIES
     (WORK CLASS LARGE_ESTIMATED_COST WORK TYPE DML
      FOR TIMERONCOST FROM 9999 TO UNBOUNDED,
      WORK CLASS LARGE_CARDINALITY WORK TYPE DML
      FOR CARDINALITY FROM 1000 TO UNBOUNDED)

Example 2: Create a work class set named DML_SELECTS that has a work class representing all DML SELECT statements that do not contain a DELETE, INSERT, MERGE, or UPDATE statement.

   CREATE WORK CLASS SET DML_SELECTS
     (WORK CLASS SELECT_CLASS WORK TYPE READ)