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0 SELECT STATEMENT Optimizer=ALL_ROWS (Cost=322 Card=319 Bytes=11803)
1 0 TABLE ACCESS (BY INDEX ROWID) OF 'TARGET' (Cost=2 Card=1 Bytes=29)
2 1 NESTED LOOPS (Cost=322 Card=319 Bytes=11803)
3 2 TABLE ACCESS (FULL) OF 'DRIVER' (Cost=3 Card=319 Bytes=2552)
4 2 INDEX (RANGE SCAN) OF 'T_PK' (UNIQUE) (Cost=1 Card=1)
is using a feature called 'prefetch'.
More about it:
http://www.oracle.com/technology/products/oracle9i/daily/dec17.html
http://forums.oracle.com/forums/message.jspa?messageID=4236898
