ALTER WORK ACTION SET statement

The ALTER WORK ACTION SET statement alters a work action set by adding, altering, or dropping work actions within the work action 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 at least one of the following authorities:

SQLADM authority, only if every alteration clause is a COLLECT clause
WLMADM authority
DBADM authority

Syntax

work-action-definition

action-types-clause

threshold-predicate-clause

threshold-exceeded-actions

collect-activity-data-clause

histogram-template-clause

work-action-alteration

alter-action-types-clause

alter-threshold-exceeded-actions

alter-collect-activity-data-clause

Notes:

¹ The ADD, ALTER, and DROP clauses are processed in the order in which they are specified.
² The ENABLE or DISABLE clause can only be specified once in the same statement.
³ Only one work action of the same threshold type can be applied to a single work class at a time. When altering a threshold work action, the threshold predicate cannot be changed.
⁴ The DETAILS keyword is the minimum to be specified, followed by the option separated by a comma.
⁵ This clause does not apply to thresholds.
⁶ The same clause must not be specified more than once.
⁷ The same clause must not be specified more than once.
⁸ If an existing work action does not have a threshold-exceeded action defined for it and it is being altered to become a threshold work action, then either STOP EXECUTION or CONTINUE must be specified, and if COLLECT ACTIVITY DATA is not specified, then COLLECT ACTIVITY DATA NONE is the default.
⁹ The DETAILS keyword is the minimum to be specified, followed by the option separated by a comma.

Description

work-action-set-name

Identifies the work action set that is to be altered. This is a one-part name. It is an SQL identifier (either ordinary or delimited). The work-action-set-name must identify a work action set that exists at the current server (SQLSTATE 42704).

ADD

Adds a work action to the work action set.

WORK ACTION work-action-name

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

ON WORK CLASS work-class-name

Specifies the work class that identifies the database activities to which this work action will apply. The work-class-name must exist in the work-class-set-name at the current server (SQLSTATE 42704).

MAP ACTIVITY

Specifies a work action of mapping the activity. This action can only be specified if the object for which this work action set is defined is a service superclass (SQLSTATE 5U034).

WITH NESTED or WITHOUT NESTED

Specifies whether or not activities that are nested under this activity are mapped to the service subclass. The default is WITH NESTED.

WITH NESTED: All database activities that have a nesting level of zero that are classified under the work class, and all database activities nested under this activity, are mapped to the service subclass; that is, activities with a nesting level greater than zero are run under the same service class as activities with a nesting level of zero.
WITHOUT NESTED: Only database activities that have a nesting level of zero that are classified under the work class are mapped to the service subclass. Database activities that are nested under this activity are handled according to their activity type.

TO service-subclass-name

Specifies the service subclass to which activities are to be mapped. The service-subclass-name must already exist in the service-superclass-name at the current server (SQLSTATE 42704). The service-subclass-name cannot be the default service subclass, SYSDEFAULTSUBCLASS (SQLSTATE 5U018).

WHEN

Specifies the threshold that will be applied to the database activity that is associated with the work class for which this work action is defined. A threshold can only be specified if the database manager object for which this work action set is defined is a database (SQLSTATE 5U034). None of these thresholds apply to internal database activities initiated by the database manager or to database activities generated by administrative SQL routines.

threshold-predicate-clause: For a description of valid threshold types, see the CREATE THRESHOLD statement.
threshold-exceeded-actions: For a description of valid threshold-exceeded actions, see the CREATE THRESHOLD statement.

PREVENT EXECUTION

Specifies that none of the database activities associated with the work class for which this work action is defined will be allowed to run (SQLSTATE 5U033).

COUNT ACTIVITY

Specifies that all of the database activities associated with the work class are to be run and that each time one is run, the counter for the work class will be incremented.

COLLECT ACTIVITY DATA

Specifies that data about each activity associated with the work class for which this work action is defined is to be sent to any active activities event monitor when the activity completes.

collect-activity-data-clause

ON COORDINATOR MEMBER

Specifies that the activity data is to be collected at only the coordinator member of the activity.

ON ALL MEMBERS

Specifies that the activity data is to be collected at all members on which the activity is processed. For predictive thresholds, activity information is collected at all members only if you also specify the CONTINUE action for exceeded thresholds. For reactive thresholds, the ON ALL MEMBERS clause has no effect and activity information is always collected only at the coordinator member. For both predictive and reactive thresholds, any input data values, section information, or values will be collected only at the coordinator member.

WITHOUT DETAILS

Specifies that data about each activity associated with the work class for which this work action is defined should be sent to any active activities event monitor, when the activity completes execution. Details about statement, compilation environment, and section environment data are not sent.

WITH

DETAILS: Specifies that statement and compilation environment data is to be sent to any active activities event monitor, for those activities that have them. Section environment data is not sent.

SECTION

Specifies that statement, compilation environment and section environment data is to be sent to any active activities event monitor for those activities that have them. DETAILS must be specified if SECTION is specified.

INCLUDE ACTUALS BASE

Specifies that section actuals should also be collected on any partition where the activity data is collected. For section actuals to be collected, either INCLUDE ACTUALS clause must be specified or the section_actuals database configuration parameter must be set.

The effective setting for the collection of section actuals is the combination of the INCLUDE ACTUALS clause, the section_actuals database configuration parameter, and the <collectsectionactuals> setting specified on the WLM_SET_CONN_ENV routine. For example, if INCLUDE ACTUALS BASE is specified, yet the section_actuals database configuration parameter value is NONE and <collectsectionactuals> is set to NONE, then the effective setting for the collection of section actuals is BASE.

BASE specifies that the following actuals should be enabled and collected during the activity's execution:

Basic operator cardinality counts
Statistics for each object referenced (DML statements only)

AND VALUES

Specifies that input data values are to be sent to any active activities event monitor, for those activities that have them.

NONE

Specifies that activity data should not be collected for each activity that is associated with the work class for which this work action is defined.

COLLECT AGGREGATE ACTIVITY DATA

Specifies that aggregate activity data is to be captured for activities that are associated with the work class for which this work action is defined and sent to the statistics event monitor, if one is active. This information is collected periodically on an interval that is specified by the wlm_collect_int database configuration parameter. The default is COLLECT AGGREGATE ACTIVITY DATA BASE. This clause cannot be specified for a work action defined in a work action set that is applied to a database.

BASE

Specifies that basic aggregate activity data should be captured for activities associated with the work class for which this work action is defined and sent to the statistics event monitor, if one is active. Basic aggregate activity data includes:

Estimated activity cost high watermark
Rows returned high watermark
Temporary table space usage high watermark. Only activities that have an SQLTEMPSPACE threshold applied to them participate in this high watermark.
Activity life time histogram
Activity queue time histogram
Activity execution time histogram

EXTENDED

Specifies that all aggregate activity data should be captured for activities associated with the work class for which this work action is defined and sent to the statistics event monitor, if one is active. This includes all basic aggregate activity data plus:

Activity data manipulation language (DML) estimated cost histogram
Activity DML inter-arrival time histogram

ENABLE or DISABLE

Specifies whether or not the work action is to be considered when database activities are submitted. The default is ENABLE.

ENABLE: Specifies that the work action is enabled and will be considered when database activities are submitted.
DISABLE: Specifies that the work action is disabled and will not be considered when database activities are submitted.

histogram-template-clause

Specifies histogram templates to use when collecting aggregate activity data for activities associated with the work class to which this work action is assigned. Aggregate activity data is only collected for the work class when the work action type is COLLECT AGGREGATE ACTIVITY DATA.

ACTIVITY LIFETIME HISTOGRAM TEMPLATE template-name: Specifies the template that describes the histogram used to collect statistical data about the duration, in milliseconds, of database activities running during a specific interval. The database activities are those associated with the work class to which this work action is assigned. This time includes both time queued and time executing. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified, with either the BASE or EXTENDED option.
ACTIVITY QUEUETIME HISTOGRAM TEMPLATE template-name: Specifies the template that describes the histogram used to collect statistical data about the length of time, in milliseconds, that database activities are queued during a specific interval. The database activities are those associated with the work class to which this work action is assigned. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified, with either the BASE or EXTENDED option.
ACTIVITY EXECUTETIME HISTOGRAM TEMPLATE template-name: Specifies the template that describes the histogram used to collect statistical data about the length of time, in milliseconds, that database activities are executing during a specific interval. The database activities are those associated with the work class to which this work action is assigned. This time does not include the time spent queued. Activity execution time is collected in this histogram at each member where the activity executes. On the activity's coordinator member, this is the end-to-end execution time (that is, the life time less the time spent queued). On non-coordinator members, this is the time that these members spend working on behalf of the activity. During the execution of a given activity, the database manager might present work to a non-coordinator member more than once, and each time the non-coordinator member will collect the execution time for that occurrence of the activity. Therefore, the counts in the execution time histogram might not represent the actual number of unique activities that executed on a member. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified, with either the BASE or EXTENDED option.
ACTIVITY ESTIMATEDCOST HISTOGRAM TEMPLATE template-name: Specifies the template that describes the histogram used to collect statistical data about the estimated cost, in timerons, of DML activities associated with the work class to which this work action is assigned. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified with the EXTENDED option.
ACTIVITY INTERARRIVALTIME HISTOGRAM TEMPLATE template-name: Specifies the template that describes the histogram used to collect statistical data about the length of time, in milliseconds, between the arrival of one DML activity and the arrival of the next DML activity, for any activity associated with the work class to which this work action is assigned. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified with the EXTENDED option.

ALTER

Alters the definition of the work action. You can change the work class to which this work action applies, and the action that is to be applied to the database activity that falls within the work class.

WORK ACTION work-action-name

Identifies the work action. The work-action-name must identify a work action that exists at the current server under this work action set (SQLSTATE 42704).

SET WORK CLASS work-class-name

MAP ACTIVITY

Specifies a work action of mapping the activity. This action can only be specified if the object for which this work action set is defined is a service superclass (SQLSTATE 5U034).

WITH NESTED or WITHOUT NESTED

Specifies whether or not activities that are nested under this activity are mapped to the service subclass. The default is WITH NESTED.

WITH NESTED: All database activities that have a nesting level of zero that are classified under the work class, and all database activities nested under this activity are mapped to the service subclass.
WITHOUT NESTED: Only database activities that have a nesting level of zero that are classified under the work class are mapped to the service subclass. Database activities that are nested under this activity are handled according to their activity type.

TO service-subclass-name

WHEN

Specifies the threshold to be altered for the database activity that is associated with the work class for which this work action is defined.

threshold-predicate-clause: For a description of valid threshold types, see the CREATE THRESHOLD statement.
PERFORM ACTION: When altering the value of the threshold predicate condition, specifies that the threshold exceeded action is not changed. The work action must be a threshold (SQLSTATE 42613).
alter-threshold-exceeded-actions: For a description of valid alter-threshold-exceeded-actions, see threshold-exceeded-actions in the CREATE THRESHOLD statement.
EXCEEDED: Specifies to keep the same threshold predicate that was specified originally for this altered threshold. The work action must be a threshold (SQLSTATE 42613).

PREVENT EXECUTION

Specifies that none of the database activities associated with the work class for which this work action is defined will be allowed to run (SQLSTATE 5U033).

COUNT ACTIVITY

Specifies that all of the database activities associated with the work class are to be run and that each time one is run, the counter for the work class will be incremented.

COLLECT ACTIVITY DATA

Specifies that data about each activity associated with the work class for which this work action is defined is to be sent to any active activities event monitor when the activity completes.

alter-collect-activity-data-clause

ON COORDINATOR MEMBER

Specifies that the activity data is to be collected only at the coordinator member of the activity.

ON ALL MEMBERS

Specifies that activity data is to be collected at all members where the activity is processed. On remote members, a record for the activity may be captured multiple times as the activity comes and goes on those members. If the AND VALUES clause is specified, activity input values will be collected only for the members of the coordinator.

WITHOUT DETAILS

Specifies that data about each activity that is associated with the work class for which this work action is defined should be sent to any active activities event monitor when the activity completes execution. Details about statement, compilation environment, and section environment data are not sent.

WITH

DETAILS: Specifies that statement and compilation environment data is to be sent to any active activities event monitor, for those activities that have them. Section environment data is not sent.

SECTION

Specifies that statement, compilation environment, section environment data, and section actuals are to be sent to any active activities event monitor for those activities that have them. DETAILS must be specified if SECTION is specified. Section actuals will be collected on any member where the activity data is collected.

INCLUDE ACTUALS BASE

BASE specifies that the following actuals should be enabled and collected during the activity's execution:

Basic operator cardinality counts
Statistics for each object referenced (DML statements only)

AND VALUES

Specifies that input data values are to be sent to any active activities event monitor, for those activities that have them.

NONE

Specifies that activity data should not be collected for each activity that is associated with the work class for which this work action is defined.

COLLECT AGGREGATE ACTIVITY DATA

BASE

Estimated activity cost high watermark
Rows returned high watermark
Temporary table space usage high watermark
Activity life time histogram
Activity queue time histogram
Activity execution time histogram

EXTENDED

Activity DML estimated cost histogram
Activity DML inter-arrival time histogram

ACTIVITY LIFETIME HISTOGRAM TEMPLATE template-name

Specifies the template that describes the histogram used to collect statistical data about the duration, in milliseconds, of database activities running during a specific interval. This time includes both time queued and time executing. The database activities are those associated with the work class to which this work action is assigned. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified, with either the BASE or EXTENDED option.

ACTIVITY QUEUETIME HISTOGRAM TEMPLATE template-name

Specifies the template that describes the histogram used to collect statistical data about the length of time, in milliseconds, that database activities are queued during a specific interval. The database activities are those associated with the work class to which this work action is assigned. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified, with either the BASE or EXTENDED option.

ACTIVITY EXECUTETIME HISTOGRAM TEMPLATE template-name

Specifies the template that describes the histogram used to collect statistical data about the length of time, in milliseconds, that database activities are executing during a specific interval. The database activities are those associated with the work class to which this work action is assigned. This time does not include the time spent queued. Activity execution time is collected in this histogram at each member where the activity executes. On the activity's coordinator member, this is the end-to-end execution time (that is, the life time less the time spent queued). On non-coordinator members, this is the time that these members spend working on behalf of the activity. During the execution of a given activity, the database manager might present work to a non-coordinator member more than once, and each time the non-coordinator member will collect the execution time for that occurrence of the activity. Therefore, the counts in the execution time histogram might not represent the actual number of unique activities that executed on a member. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified, with either the BASE or EXTENDED option.

ACTIVITY ESTIMATEDCOST HISTOGRAM TEMPLATE template-name

Specifies the template that describes the histogram used to collect statistical data about the estimated cost, in timerons, of data manipulation language (DML) activities associated with the work class to which this work action is assigned. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified with the EXTENDED option.

ACTIVITY INTERARRIVALTIME HISTOGRAM TEMPLATE template-name

Specifies the template that describes the histogram used to collect statistical data about the length of time, in milliseconds, between the arrival of one DML activity and the arrival of the next DML activity, for any activity associated with the work class to which this work action is assigned. The default is SYSDEFAULTHISTOGRAM. This information is only collected when the COLLECT AGGREGATE ACTIVITY DATA clause is specified with the EXTENDED option.

ENABLE or DISABLE

Specifies whether or not the work action is to be considered when database activities are submitted.

ENABLE: Specifies that the work action is enabled and will be considered when database activities are submitted.
DISABLE: Specifies that the work action is disabled and will not be considered when database activities are submitted.

DROP work-action-name

Drops the work action from the work action set. The work-action-name must identify a work action that exists at the current server under this work action set (SQLSTATE 42704).

A threshold created as part of a work action set cannot be manipulated directly. You must first disable the work action in order to disable the threshold. You can then drop the work action once the threshold is not being used. For more information about dropping a work action, see the Related tasks section.

ENABLE or DISABLE

Specifies whether or not the work action set is to be considered when database activities are submitted.

ENABLE: Specifies that the work action set is enabled and will be considered when database activities are submitted.
DISABLE: Specifies that the work action set is disabled and will not be considered when database activities are submitted.

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.
Thresholds with a queue, for example CONCURRENTDBCOORDACTIVITIES, must be disabled before they can be dropped.
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.
Syntax alternatives: The following syntax alternatives are supported for compatibility with previous versions of Db2® and with other database products. These alternatives are non-standard and should not be used.
- DATABASE PARTITION can be specified in place of MEMBER, except when the DB2_ENFORCE_MEMBER_SYNTAX registry variable is set to ON.
- DATABASE PARTITIONS can be specified in place of MEMBERS, except when the DB2_ENFORCE_MEMBER_SYNTAX registry variable is set to ON.

Examples

Example 1: Alter the DATABASE_ACTIONS work action set and add two work actions using the work class LARGE_SELECTS. For the work action ONE_CONCURRENT_SELECT, apply a concurrency threshold of 1 to control the number of activities that can run at one time, and allow a maximum of 3 to be queued. For work action BIG_ROWS_RETURNED, limit the number of rows that can be returned by database activities that fall within that class to 1 000 000.
```
   ALTER WORK ACTION SET DATABASE_ACTIONS
     ADD WORK ACTION ONE_CONCURRENT_SELECT ON WORK CLASS LARGE_SELECTS
        WHEN CONCURRENTDBCOORDACTIVITIES > 1
           AND QUEUEDACTIVITIES > 3 STOP EXECUTION
     ADD WORK ACTION BIG_ROWS_RETURNED ON WORK CLASS LARGE_SELECTS
        WHEN SQLROWSRETURNED > 1000000 STOP EXECUTION
```
Example 2: Alter the ADMIN_APPS_ACTIONS work action set to alter the MAP_SELECTS work action to map all activities that run in super service class ADMIN_APPS under the work class SELECT_CLASS to the service subclass ALL_SELECTS. Also add a new work action called MAP_UPDATES that maps all activities that would run in the work class UPDATE_CLASS to the service subclass ALL_SELECTS.
```
   ALTER WORK ACTION SET ADMIN_APPS_ACTIONS
     ALTER WORK ACTION MAP_SELECTS MAP ACTIVITY TO ALL_SELECTS
     ADD WORK ACTION MAP_UPDATES ON WORK CLASS UPDATE_CLASS
       MAP ACTIVITY TO ALL_SELECTS
```