Logical reads, physical reads, and 2K I/O

With 2K I/O, the number of times that a page is found in cache for a query is logical reads minus physical reads. When the total number of logical reads and physical reads is the same for a table scan, it means that each page was read from disk and accessed only once during the query.

When pages for the query are found in cache, logical reads are higher than physical reads. This happens frequently with pages from higher levels of the index, since they are reused often, and tend to remain in cache.