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使用DBMS_STATS.restore 恢复统计信息
我们可以恢复之前的统计信息,生成原本的执行计划 SQL> BEGIN 2 DBMS_STATS.restore_table_stats(ownname => ‘DAO‘,tabname => ‘TEST_STATS‘,as_of_timestamp => ‘27-JUN-14 05.40.33.314757 PM +08:00‘); 3 END ; 4 / PL/SQL procedure successfully completed.
SQL> select count(*) from test_stats ; COUNT(*) ---------- 75675
Execution Plan
----------------------------------------------------------
Plan hash value: 2395052010
------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Cost (%CPU)| Time |
------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 44 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | | |
| 2 | INDEX FAST FULL SCAN| DAO_STATS_PK | 75675 | 44 (0)| 00:00:01 |
------------------------------------------------------------------------------
Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
1081 consistent gets
0 physical reads
0 redo size
528 bytes sent via SQL*Net to client
523 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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