帮忙解释下oracle执行计划的含义
bhwhy 2008-12-22 04:00:02 在sqlplus中查看一个语句的执行计划,可是看不明白,哪位帮忙解释一下。
実行計画
----------------------------------------------------------
0 INSERT STATEMENT Optimizer=ALL_ROWS (Cost=5 Card=1 Bytes=206
)
1 0 COUNT
2 1 VIEW (Cost=5 Card=1 Bytes=206)
3 2 COUNT
4 3 VIEW (Cost=5 Card=1 Bytes=193)
5 4 SORT (ORDER BY) (Cost=5 Card=1 Bytes=173)
6 5 NESTED LOOPS (Cost=4 Card=1 Bytes=173)
7 6 VIEW (Cost=3 Card=1 Bytes=31)
8 7 FILTER
9 8 SORT (GROUP BY) (Cost=3 Card=1 Bytes=30)
10 9 INDEX (RANGE SCAN) OF 'SYS_C003749' (IND
EX (UNIQUE)) (Cost=3 Card=1 Bytes=30)
11 6 TABLE ACCESS (BY INDEX ROWID) OF 'FKOGD24' (TA
BLE) (Cost=1 Card=1 Bytes=142)
12 11 INDEX (UNIQUE SCAN) OF 'SYS_C003741' (INDEX
(UNIQUE)) (Cost=1 Card=1)
統計
----------------------------------------------------------
0 recursive calls
9 db block gets
22 consistent gets
0 physical reads
1492 redo size
535 bytes sent via SQL*Net to client
2969 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
3 sorts (memory)
0 sorts (disk)
2 rows processed
我主要想知道这个语句的用时,有点不明白啊。