Exadata Smart Scan

Front 1

Advantages of the Database Viewpoint unchanged

Back 1

•Competitor: “Exadata is still Oracle!”
•Right – that is actually a good thing because:
•No change is needed for the Database Design
•No change is needed for the Application Code
•Migration to Exadata is relatively easy therefore
•DBA knowledge remains valid

Front 2

What is the Exadata Smart Scan Idea

Back 2

• “The fastest way of doing something is not to do it”
• Do not deliver the whole Data Volume up to the DB Layer!
• Instead, filter resp. project already on the Storage Layer!
• We want DB Intelligence built into the Storage Layer ...

Front 3

Smart Scan, what is predicate filtering?

Back 3

– Only the requested rows are returned to the database server
rather than all the rows in a table.

Front 4

Smart Scan, what is column filtering

Back 4

– Only the requested columns are returned to the database server rather than all the columns in a table.

Front 5

Smart Scan... Query Example

Back 5

Example:

SQL> SELECT col1,col2 FROM t WHERE condition;

Front 6

Smart Scan Prerequisites

Back 6

• Smart Scan is only possible for Full Table Scans or Full
Index Scans.
• Smart Scan can only be used for Direct-Path Reads:
• Direct-path reads are automatically used for parallel queries.
• Direct-path reads may also be used for serial queries.