Databases Reference
In-Depth Information
We can see that, using the
/*+
FULL(C)
*/
hint in our query, the execution plan changes,
and the access to the
CUSTOMERS
table is made through a full table scan instead of using
indexes, as before.
In step 5, we changed our hint, informing the optimizer that we are not interested in the
complete dataset, but only in the first 10 rows, using the hint
/*+
FIRST_ROWS
(10)
*/
.
The execution plan changes again; we can see the result in the following screenshot:
We can see that the optimizer has chosen to use the
CUSTOMERS_YOB_BIX
index to answer
our query, as in step 3.
