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。

<!-- Code highlighting produced by Actipro CodeHighlighter (freeware) http://www.CodeHighlighter.com/ -->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