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没错,10秒是不是很快,可比起以前优化来说变化太大了,实际上也没有用10秒!把计划贴上来看一下!
SQL> show parameter optimizer_index_cost_adj
NAME TYPE VALUE
------------------------------------ ------- ------------------------------
optimizer_index_cost_adj integer 100
SQL> set autotrace traceonly
SQL> select * from kc22 where akb020='100004' and akc190='30048174120060825' and akc220='265';
Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE
1 0 TABLE ACCESS (BY INDEX ROWID) OF 'KC22'
2 1 INDEX (RANGE SCAN) OF 'INDEX_KC22_T' (NON-UNIQUE)
Statistics
----------------------------------------------------------
312 recursive calls
0 db block gets
170 consistent gets
66 physical reads
264 redo size
3796 bytes sent via SQL*Net to client
425 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
4 sorts (memory)
0 sorts (disk)
1 rows processed
表分析后
SQL> set autotrace traceonly
SQL> select * from kc22 where akb020='100004' and akc190='30048174120060825' and akc220='265';
Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=10 Card=1 Bytes=194)
1 0 TABLE ACCESS (BY INDEX ROWID) OF 'KC22' (Cost=10 Card=1 By
tes=194)
2 1 INDEX (RANGE SCAN) OF 'PK_KC22_T' (UNIQUE) (Cost=9 Card=
1)
Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
10 consistent gets
8 physical reads
0 redo size
3796 bytes sent via SQL*Net to client
425 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed |
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