For example, if the shift number is 2, "H" is substituted by "J," "z" is substituted by "b," and so on.
例如，如果偏移数是 2，那么 “H” 被替换为 “J”，“z” 被替换为 “b”，以此类推。
2
H - Current history event number.
h -当前历史事件的数值。
3
Because of the number of table scans and table sorts in the TPC-H workload, prefetching data from disks into memory is important for optimal performance.