oracle hint_noappend_parallel

wisdomone1發表於2012-12-20
OracleAPPParallel
1,hint
model_min_analysis
 1,/*+ model_min_analysis */
 2,忽略一些spreadsheet rules的編譯期間的最佳化工作,這個主要指的具體有依賴性關係的圖表分析
 3,其它一些spreadsheet最佳化,比如構建filter產生spreadsheet訪問結構和有限的規則pruning
 
 
 noappend
 1,讓插入表時透過非並行模式且以傳統方式插入資料
 3,傳統方式是序列方式插入資料
 2,direct path insert是並行模式插入
 4,何謂direct path insert
 
 SQL> create table t_append(a int);
表已建立。
SQL> explain plan for insert into t_append select level from dual connect by lev
el<=1e5;
已解釋。
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 1236776825
--------------------------------------------------------------------------------
--
| Id  | Operation                     | Name     | Rows  | Cost (%CPU)| Time
 |
--------------------------------------------------------------------------------
--

PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
|   0 | INSERT STATEMENT              |          |     1 |     2   (0)| 00:00:01
 |
|   1 |  LOAD TABLE CONVENTIONAL      | T_APPEND |       |            |
 |
|*  2 |   CONNECT BY WITHOUT FILTERING|          |       |            |
 |
|   3 |    FAST DUAL                  |          |     1 |     2   (0)| 00:00:01
 |
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
--

Predicate Information (identified by operation id):
---------------------------------------------------
   2 - filter(LEVEL<=1e5)
已選擇15行。
SQL> explain plan for insert /*+ append */ into t_append select level from dual
connect by level<=1e5;
已解釋。
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 1541388231
--------------------------------------------------------------------------------
--
| Id  | Operation                     | Name     | Rows  | Cost (%CPU)| Time
 |
--------------------------------------------------------------------------------
--

PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
|   0 | INSERT STATEMENT              |          |     1 |     2   (0)| 00:00:01
 |
|   1 |  LOAD AS SELECT               | T_APPEND |       |            |
 |
|*  2 |   CONNECT BY WITHOUT FILTERING|          |       |            |
 |
|   3 |    FAST DUAL                  |          |     1 |     2   (0)| 00:00:01
 |
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
--

Predicate Information (identified by operation id):
---------------------------------------------------
   2 - filter(LEVEL<=1e5)
已選擇15行。

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