Effectively this makes the pairs of FLUSH INDEX_STATISTICS / FLUSH CHANGED_PAGE_BITMAPS and FLUSH USER_STATISTICS / RESET CHANGE_PAGE_BITMAPS joined, issuing either command has the effect of both. The first is relatively benign but has a bug that FLUSH INDEX_STATISTICS starts requiring SUPER instead of RELOAD privilege. The second pair destroys bitmaps if one issues FLUSH USER_STATISTICS, which is more serious.
Effectively this makes the pairs of FLUSH INDEX_STATISTICS / FLUSH CHANGED_ PAGE_BITMAPS and FLUSH USER_STATISTICS / RESET CHANGE_PAGE_BITMAPS joined, issuing either command has the effect of both. The first is relatively benign but has a bug that FLUSH INDEX_STATISTICS starts requiring SUPER instead of RELOAD privilege. The second pair destroys bitmaps if one issues FLUSH USER_STATISTICS, which is more serious.