Oracle SQL：减少commit次数以提高sql的性能

详细的分析http://grassbell.itpub.net/post/26/926

Oracle数据库中，当需要批量对数据库执行插入或者更新操作时候，减少commit的次数，从而减少transaction的数量，而在每个transaction中包含合适的数据处理量，可以提高sql的性能。测试sql如下：

SQL>
SQL> set timing on
SQL> set serveroutput on
SQL>
SQL> drop table testex;

Table dropped.

Elapsed: 00:00:00.05
SQL>
SQL> create table testex (
2 n number,
3 a varchar2(10),
4 b varchar2(100),
5 c number,
6 d date);

Table created.

Elapsed: 00:00:00.00
SQL>
SQL> begin
2 for i in 1..200000 loop
3 insert into testex values(i,'test','testtesttestteset',i,sysdate);
4 commit;
5 end loop;
6 commit;
7
8 end;
9 /

PL/SQL procedure successfully completed.

Elapsed: 00:00:24.06
SQL>
SQL> delete from testex;

200000 rows deleted.

Elapsed: 00:00:14.09
SQL> commit;

Commit complete.

Elapsed: 00:00:00.00
SQL>
SQL> begin
2 for i in 1..200000 loop
3 insert into testex values(i,'test','testtesttestteset',i,sysdate);
4 end loop;
5 commit;
6
7 end;
8 /

PL/SQL procedure successfully completed.

Elapsed: 00:00:17.09
SQL>
SQL> spool off