CREATE MULTISET TABLE XXXXX.TEST_3 AS XXXXX.TEST_1 WITH DATA AND STATS;
HELP STAT XXXXX.TEST_3;
There are no dupicates on multiset tables.My questions is why stats are not copied from mutiset table to set table. It is not useless stat. I know stats will be copied from mutiset table to multiset table.
Btw, this behaviour is fully documented in the manuals:
If all columns in a MULTISET source table are non-unique, and if the target table is a SET table, then the system does not copy statistics to the target table. This is because of the possible violation of the rule of equal cardinalities in the source and target tables: if there are duplicate rows in the source table, the system eliminates them before copying to the target table, resulting in unequal cardinalities between the 2 tables.