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

Minor comments:

    Please add a comment to have_64_keys explaining what part of the
    metadata confirms that max_indexes = 64.
    Typos: line 39: s/check/checks, line 41: s/skipping/skip. These
    are repeated in other test headers.

    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.