Table scan cost

When a query requires a table scan, Adaptive Server reads each page of the table from disk into the data cache and checks the data values (if there is a where clause) and returns qualifying rows.

Table scans are performed:

The cost of a table scan depends on the size of the table and the I/O size.

NoteReference to Large I/Os are on a 2K logical page size server. If you have an 8K page size server, the basic unit for the I/O is 8K. If you have a 16K page size server, the basic unit for the I/O is 16K.