TABLE::initialize_quick_structures() takes 0.5% in oltp_read_only

void TABLE::initialize_quick_structures()

{

  bzero(quick_rows, sizeof(quick_rows));

  bzero(quick_key_parts, sizeof(quick_key_parts));

  bzero(quick_costs, sizeof(quick_costs));

  bzero(quick_n_ranges, sizeof(quick_n_ranges));

}

1. These members consume 1536 of 3520 bytes (44%) of TABLE for no good reason.
2. I doubt these arrays have to be fully initialized. I'd say they have to be initialized up to the number of indexes in the table.
3. Assuming these are per-key variables, they should be part of something like KEY rather than something like TABLE.
4. I generally recommend not using pre-initialization for performance reasons, but also because it tends to hide bugs from uninit-var detectors.