Exadata uses smart scans, which are executed in________.
A.
Exadata Storage Server cells
B.
Database Server node memory
C.
Database Server node CPUs
D.
Exadata does not use smart scans.
Explanation:
The Oracle Exadata Database Machine brings database performance to a whole
new level, but have you ever wondered what exactly makes it so fast? Several components of the
Oracle Exadata Database Machine, such as Oracle Database 11g Release 2; Oracle Exadatas
Smart Flash Cache, Hybrid Columnar Compression, and SmartScan features; and InfiniBand
interconnect, help deliver high performance. One of the key technologies that supports this
performance is the storage index, which is not a regular database index. Storage indexes reside in
the memory of the storage serversalso called storage cellsand significantly reduce
unnecessary I/O by excluding irrelevant database blocks in the storage cells.
Oracle Exadata I/O and Smart Scan
Storage in Oracle Exadata changes query processing so that not all blocks have to go to the
database server for that server to determine which rows might satisfy a query. Oracle Exadatas
Smart Scan feature enables certain types of query processing to be done in the storage cell. With
Smart Scan technology, the database nodes send query details to the storage cells via a protocol
known as iDB (Intelligent Database). With this information, the storage cells can take over a large
portion of the data-intensive query processing. Oracle Exadata storage cells can search storage
disks with added intelligence about the query and send only the relevant bytes, not all the
database blocks, to the database nodeshence the term smart scan.
Reference: http://www.oracle.com/technetwork/issue-archive/2011/11-may/o31exadata-354069.html