Relationship between physical and logical reads

If Adaptive Server reads a page from disk, it is counted as a physical and a logical read. The cost of logical I/O is always greater than or equal to physical I/O.

Logical I/O always reports 2K data pages. Physical reads and writes are reported in buffer-sized units. Multiple pages that are read in a single I/O operation are treated as a unit: they are read, written, and moved through the cache as a single buffer.