Code review comment for lp:~akopytov/percona-server/bug1131187-5.6

Everything is OK. Just one follow-up question:

    - Upstream read_view_create_low() allocates the read view and its
      trx_ids in a single allocation. After the fix we are back to
      two allocations. It is possible to have a single allocation
      for us too, but I'm not sure whether it's worth it: on one
      hand, it's a single ut_realloc() anyway when trx_ids grows, on
      the other, reallocating the whole view would improve access
      locality and saves one memcpy() in read_view_clone(). Shall we
      open a bug for this or there is no benefit?