The second part of the autotrace output are a part of the session statistics.
Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
24 consistent gets
0 physical reads
0 redo size
1598 bytes sent via SQL*Net to client
396 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
15 rows processed
SELECT
statname.display_name AS "Statistics Name",
sesstat.value
FROM
v$sesstat sesstat,
V$STATNAME statname
WHERE
sesstat.statistic# = statname.statistic#
AND sesstat.sid = SYS_CONTEXT( 'USERENV', 'SID' )
ORDER BY
statname.display_name;
recursive_calls : Number of SQL statements executed in order to execute your SQL statement
db block gets and consistent gets are the most important part of the output. They represent the Oracle Database - Buffer IO (Logical IO). The less we latch, the better.
Oracle Database - Physical Read : Number of physical reads from the datafiles into the buffer cache
Oracle Database - Redo Size statistics : Total amount of redo generated in bytes during the execution of this statement
Oracle Database - SQL*Net Statistics