Changes the impact setting for a running utility. Using
this command, you can:
- throttle a utility that was invoked in unthrottled mode
- unthrottle a throttled utility (disable throttling)
- reprioritize a throttled utility (useful if running multiple simultaneous
throttled utilities)
Authorization
One of the following:
- sysadm
- sysctrl
- sysmaint
- sysmon
Required connection
Instance. If there
is more than one partition on the local machine, the attachment should
be made to the correct partition. For example, suppose there are two
partitions and a
LIST UTILITIES command resulted
in the following output:
ID = 2
Type = BACKUP
Database Name = IWZ
Partition Number = 1
Description = online db
Start Time = 07/19/2007 17:32:09.622395
State = Executing
Invocation Type = User
Throttling:
Priority = Unthrottled
Progress Monitoring:
Estimated Percentage Complete = 10
Total Work = 97867649689 bytes
Completed Work = 10124388481 bytes
The instance attachment must be made to partition 1 in
order to issue a
SET UTIL_IMPACT_PRIORITY command
against the utility with ID 2. To do this, set DB2NODE=1 in the environment
and then issue the instance attachment command.
Command syntax
>>-SET UTIL_IMPACT_PRIORITY FOR--utility-id--TO--priority------><
Command parameters
- utility-id
- ID of the utility whose impact setting will be updated. IDs of
running utilities can be obtained with the LIST UTILITIES command.
- TO priority
- Specifies an instance-level limit on the impact associated with
running a utility. A value of 100 represents the highest priority
and 1 represents the lowest priority. Setting priority to
0 will force a throttled utility to continue unthrottled. Setting priority to
a non-zero value will force an unthrottled utility to continue in
throttled mode.
Examples
The following example unthrottles
the utility with ID 2.
SET UTIL_IMPACT_PRIORITY FOR 2 TO 0
The
following example throttles the utility with ID 3 to priority 10.
If the priority was 0 before the change then a previously unthrottled
utility is now throttled. If the utility was previously throttled
(priority had been set to a value greater than zero), then the utility
has been reprioritized.
SET UTIL_IMPACT_PRIORITY FOR 3 TO 10
Relationship between UTIL_IMPACT_LIM and UTIL_IMPACT_PRIORITY
settings
The database manager configuration parameter util_impact_lim sets
the limit on the impact throttled utilities can have on the overall
workload of the machine. 0-99 is a throttled percentage, 100 is no
throttling.
The SET UTIL_IMPACT_PRIORITY command
sets the priority that a particular utility has over the resources
available to throttled utilities as defined by the util_impact_lim configuration
parameter. (0 = unthrottled)
Using the backup utility as an
example, if the
util_impact_lim=10, all utilities
can have no more than a 10% average impact upon the total workload
as judged by the throttling algorithm. Using two throttled utilities
as an example:
- Backup with util_impact_priority 70
- Runstats with util_impact_priority 50
Both utilities combined should have no more than
a 10% average impact on the total workload, and the utility with the
higher priority will get more of the available workload resources.
For both the backup and runstats operations, it is also possible to
declare the impact priority within the command line of that utility.
If you do not issue the SET UTIL_IMPACT_PRIORITY command,
the utility will run unthrottled (irrespective of the setting of util_impact_lim).
To
view the current priority setting for the utilities that are running,
you can use the LIST UTILITIES command.
Usage notes
Throttling requires having
an impact policy defined by setting the util_impact_lim configuration
parameter.