Neoview Control Query Default (CQD) Reference Guide (R2.5)

For any value greater than 199 a priority of 199 is used.0 through max unsigned
integer
The default value is 150.
Values
Setting this CQD lower than 150 means that automated update statistics during the
maintenance window is less likely to interfere with other work on the system, but may not
get as much done during the window. Setting this CQD to a value higher than 150 may
slow down other work during the maintenance window, but allow more tables to have
histograms generated.
Usage
Not applicableProduction usage
This setting can influence the impact on other concurrent workload while affecting the
time it takes to run update statistics, as explained in Usage.
Impact
SystemLevel
Need to be aware of the priorities at which other workloads are running. Various processes
follow preconfigured priorities. Setting the priority incorrectly could cause unexpected
behavior.
Conflicts/Synergies
Not applicableAddressing the real
problem
Neoview Release 2.4Introduced in release
Not applicableDeprecated in release
USTAT_MAX_READ_AGE_IN_MIN
Update Statistics and ReorgCategory
When performing update statistics with the NECESSARY keyword or with automation,
this is the number of minutes that are allowed to have elapsed since a histogram was
marked as read for it to be regenerated.
Histograms that were marked more than USTAT_MAX_READ_AGE_IN_MIN minutes
ago are not regenerated.
Description
Setting this CQD to a value less than 2 *
USTAT_AUTOMATION_INTERVAL is silently ignored and 2
* USTAT_AUTOMATION_INTERVAL (default value of 2880)
is used.
0 through max unsigned
integer
The default value is 5760 (4 days).
Values
Influences how frequently the histograms for a table are regenerated. If a table is being
used frequently then chances are that its histograms are also be considered for update
frequently. However, if a table is not used frequently, this CQD influences how frequently
the histograms for that table are updated.
A smaller setting reduces the number of histograms being updated if there are many tables
that have not been used within that interval. A larger setting updates histogram for many
more tables that are not being accessed that often.
Usage
Not applicableProduction usage
Influences the number of histograms that need to be regenerated and therefore the time it
takes for update statistics automation to regenerate histograms for all the tables that so
qualify.
Impact
SystemLevel
USTAT_AUTOMATION_INTERVAL sets a lower bound on this CQD.
It is influenced by USTAT_AUTO_READTIME_UPDATE_INTERVAL, which influences
how often READ_TIME is updated for the histogram. This CQD qualifies the histogram
to be regenerated – is the maximum time since READ_TIME was updated.
Conflicts/Synergies
Not applicableAddressing the real
problem
18 Managing Automated STATS Generation