Skipped Statistics collection without enabling System or User Thresholds in DBSControls

General
Teradata Employee

Skipped Statistics collection without enabling System or User Thresholds in DBSControls

We are using T14.10 version of Teradata and we have turned on UDI(ObjectUsage) recently. Ever since we turned this feature ON, we are noticing that statistics collection for some of the tables is being skipped.All the DBScontrols related to Statistics are at System Default. We did not setup any User or System Thresholds .

The documentation indicated that when UDI is enabled and SysChangeThresholdoption is set to default ,optimizer determines the Threshold percentages.Could this be the reason for skipped statistics?

If the above statement is true, how does optimizer determine to skip the stats for certain tables or even for certain stats in a table? What is Threshold at which Optimizer chooses to skip the collection of statistics?

Correct me if Im missing anything here