This node represents the scan of a list of
row identifiers
(RIDs).
Node name: RIDSCN
Represents: The
scan of a list of row identifiers (RIDs) obtained from one or more
indexes.
This operation
is considered by the optimizer when:
- Predicates are connected
by OR keywords, or there is an IN predicate.
A technique called index ORing can be used, which combines results
from multiple index accesses on the same table.
- It is beneficial
to use list prefetch for a single index access,
since sorting the row identifiers before accessing the base rows makes
the I/O more efficient.