Code review comment for lp:~sergei.glushchenko/percona-server/ps51-128-max-index

Laurynas,
> Bitmap::to_ulonglong() returns the first ulonglong-sized bytes of
> the bitmap. In case of default bitmap representation that's the
> whole bitmap, in case of the general bitmap that's a prefix only.
> It does suggest that the code in
> opt_range.cc:get_best_group_min_max() might produce suboptimal
> query plans whenever max_indexes > 64 and actual indexes (key
> parts > 64). I am not sure that we should do anything about it.

Code in opt_range.cc can be easily modified to compare prefix by using other operations of Bitmap<> class. More interesting is to construct a good testcase for this issue.