dbms_stats hidden column

table with two indexes, statistics calculated. Third index over lower(USER_NAME) created, this column is not inluded in first two indexes.

I tried to calculate statistics for hidden column:

exec dbms_stats.gather_table_stats(USER,'TAB_COL', method_opt=>'FOR COLUMNS SYS_NC00009$'); exec dbms_stats.gather_table_stats(USER,'TAB_COL', method_opt=>'FOR COLUMNS (lower(USER_NAME))');

trace for both calls shows full scan on table and full scan on third index (as expected), but also full scans on first two indexes (their last_analyzed updated after call). Why the other two indexes were also scanned ? Is my statement wrong or it is some bug ?

Best Regards ,
Petr--
http://www.freelists.org/webpage/oracle-l Received on Tue Dec 16 2014 - 08:45:34 CET