Bulk Binds对性能的提高

 当Oracle运行PL/SQL时会使用两套引擎，所有procedural code由PL/SQL engine 完成，所有SQL由SQL engine处理。所以如果Oracle从一个collection中循环执行相同的DML操作，那么为了避免两套engine切换所消耗的系统资源，可以使用bulk binds来把所有的DML操作binding到一次操作中完成。这将极大提高PL/SQL的执行效率。

　　以下是简单的测试，用两种方式插入100000条数据，可以看到效率提高了7倍左右。

  
    

   
     
   
   
     SQL
   
     >
   
      
   
     CREATE
   
      
   
     TABLE
   
      test1(  
   
     2
   
      id 
   
     NUMBER
   
     (
   
     10
   
     ),  
   
     3
   
      description 
   
     VARCHAR2
   
     (
   
     50
   
     ));  
   
     Table
   
      created  SQL
   
     >
   
      
   
     ALTER
   
      
   
     TABLE
   
      test1 
   
     ADD
   
      (  
   
     2
   
      
   
     CONSTRAINT
   
      test1_pk 
   
     PRIMARY
   
      
   
     KEY
   
      (id));  
   
     Table
   
      altered  SQL
   
     >
   
      
   
     SET
   
      TIMING 
   
     ON
   
     ;  SQL
   
     >
   
      
   
     DECLARE
   
       
   
     2
   
      TYPE id_type 
   
     IS
   
      
   
     TABLE
   
      
   
     OF
   
      test1.id
   
     %
   
     TYPE;  
   
     3
   
      TYPE description_type 
   
     IS
   
      
   
     TABLE
   
      
   
     OF
   
      test1.description
   
     %
   
     TYPE;  
   
     4
   
       
   
     5
   
      t_id id_type :
   
     =
   
      id_type();  
   
     6
   
      t_description description_type :
   
     =
   
      description_type();  
   
     7
   
      
   
     BEGIN
   
       
   
     8
   
      
   
     FOR
   
      i 
   
     IN
   
      
   
     1
   
      .. 
   
     100000
   
      LOOP  
   
     9
   
      t_id.extend;  
   
     10
   
      t_description.extend;  
   
     11
   
       
   
     12
   
      t_id(t_id.last) :
   
     =
   
      i;  
   
     13
   
      t_description(t_description.last) :
   
     =
   
      
   
     '
   
     Description: 
   
     '
   
      
   
     ||
   
      To_Char(i);  
   
     14
   
      
   
     END
   
      LOOP;  
   
     15
   
       
   
     16
   
      
   
     FOR
   
      i 
   
     IN
   
      t_id.first .. t_id.last LOOP  
   
     17
   
      
   
     INSERT
   
      
   
     INTO
   
      test1 (id, description)  
   
     18
   
      
   
     VALUES
   
      (t_id(i), t_description(i));  
   
     19
   
      
   
     END
   
      LOOP;  
   
     20
   
       
   
     21
   
      
   
     COMMIT
   
     ;  
   
     22
   
      
   
     END
   
     ;  
   
     23
   
      
   
     /
   
       PL
   
     /
   
     SQL 
   
     procedure
   
      successfully completed  Executed 
   
     in
   
      
   
     141.233
   
      seconds  SQL
   
     >
   
      
   
     truncate
   
      
   
     table
   
      test1;  
   
     Table
   
      truncated  Executed 
   
     in
   
      
   
     0.631
   
      seconds  SQL
   
     >
   
      SQL
   
     >
   
      
   
     DECLARE
   
       
   
     2
   
      TYPE id_type 
   
     IS
   
      
   
     TABLE
   
      
   
     OF
   
      test1.id
   
     %
   
     TYPE;  
   
     3
   
      TYPE description_type 
   
     IS
   
      
   
     TABLE
   
      
   
     OF
   
      test1.description
   
     %
   
     TYPE;  
   
     4
   
       
   
     5
   
      t_id id_type :
   
     =
   
      id_type();  
   
     6
   
      t_description description_type :
   
     =
   
      description_type();  
   
     7
   
      
   
     BEGIN
   
       
   
     8
   
      
   
     FOR
   
      i 
   
     IN
   
      
   
     1
   
      .. 
   
     100000
   
      LOOP  
   
     9
   
      t_id.extend;  
   
     10
   
      t_description.extend;  
   
     11
   
       
   
     12
   
      t_id(t_id.last) :
   
     =
   
      i;  
   
     13
   
      t_description(t_description.last) :
   
     =
   
      
   
     '
   
     Description: 
   
     '
   
      
   
     ||
   
      To_Char(i);  
   
     14
   
      
   
     END
   
      LOOP;  
   
     15
   
       
   
     16
   
      FORALL i 
   
     IN
   
      t_id.first .. t_id.last  
   
     17
   
      
   
     INSERT
   
      
   
     INTO
   
      test1 (id, description)  
   
     18
   
      
   
     VALUES
   
      (t_id(i), t_description(i));  
   
     19
   
       
   
     20
   
      
   
     COMMIT
   
     ;  
   
     21
   
      
   
     END
   
     ;  
   
     22
   
      
   
     /
   
       PL
   
     /
   
     SQL 
   
     procedure
   
      successfully completed  Executed 
   
     in
   
      
   
     27.52
   
      seconds  SQL
   
     >
   
      
   
     select
   
      
   
     count
   
     (
   
     *
   
     ) 
   
     from
   
      test1;   
   
     COUNT
   
     (
   
     *
   
     ) 
   
     --
   
     --------
   
      
   
      
   
     100000
   
       Executed 
   
     in
   
      
   
     0.04
   
      seconds