This node represents table scans.
Node name: TBSCAN
Represents: A
table
scan (relation scan) that retrieves rows by reading all the required
data directly from the data pages.
This type of scan is chosen
by the optimizer over an index scan when:
- The range of values
scanned occurs frequently (that is, most of
the table must be accessed).
- The table is small.
- Index
clustering is low.
- An index on the table does not exist.