A read-only application is in development and is using a test database on a Database Machine.
You are examining SQL statements from this application in an attempt to determine which ones
will benefit from the Exadata Smart scan capability.
The following is true about the tables used by the application:
1. The data for the tables has just been loaded.
2. There are no applications accessing the tables currently.
3. None of the indexes are compressed or reverse key indexes.
4. The tables use the default organization type data.
5. The only data types for the table are varchar (2), number, or date.
6. The largest number of columns for any table is 29.
7. No access is based on ROWID, or virtual columns.
Which two access paths will always generate either a set of “cell smart table scan” or a set of “cell
smart index scan” requested?
Full scans on sorted hash clustered tables executed in parallel
Full table scans on index organized tables executed in parallel.
Full table scans on heap tables executed in parallel
Full scans on index clustered tables executed in parallel
full scans on hash clustered tables executed in serially
fast full scans on B*Tree indexes executed in parallel
full index scans on B*Tree indexes executed in parallel
*Exadata is built to efficiently use the resources to return results to the end user. Toward that end
it has been designed to offload query tasks to the storage server, when possible, to reduce the
amount of data passed to the calling session. Certain criteria must be met to offload to the storage
/Full table or index scans must be used
/Direct path reads must be used to access the data
If the first requirement is not met another option can trigger the offloading mechanism:
/Parallel query is in use
*How do you know you’ve used a Smart Scan? The ‘cell smart table scan’ wait event or the ‘cell
smart index scan’ wait event will show activity indicating a Smart Scan occurred. Nothing in the
execution plan would be displayed to prove a Smart Scan was used; querying v$waitstat would be
the only way to confirm that a Smart Scan was implemented.