Addendum patch for bug #54190.
The patch caused some test failures when merged to 5.5 because, unlike 5.1, it utilizes Item_cache_row to actually cache row values. The problem was that Item_cache_row::bring_value() essentially did nothing. In particular, it did not update its null_value, so all Item_cache_row objects were always having their null_values set to TRUE. This went unnoticed previously, but now when Arg_comparator::compare_row() actually depends on the row's null_value to evaluate the comparison, the problem has surfaced. Fixed by calling the underlying item's bring_value() and updating null_value in Item_cache_row::bring_value(). Since the problem also exists in 5.1 code (albeit hidden, since the relevant code is not used anywhere), the addendum patch is against 5.1.
Showing
Please register or sign in to comment