The updatable views contain statistical information used by the optimizer. Some columns in these views may be changed to investigate the performance of hypothetical databases. An object (table, column, function, or index) will appear in the updatable catalog view for a given user only if that user created the object, holds CONTROL privilege on the object, or holds explicit DBADM privilege. These views are found in the SYSSTAT schema. They are defined on top of the SYSCAT views.
Before changing any statistics for the first time, it is advised to issue the RUNSTATS command so that all statistics will reflect the current state.
See SQL Reference for more information, including rules for updating catalog statistics.