Oracle 12C 新特性 Temporary UNDO 临时回滚段

Oracle 12C 新特性 Temporary UNDO 可以减少存储在undo表空间的生成量和重做日志的生成

首页 → 数据库技术

背景：

阅读新闻

Oracle 12C 新特性 Temporary UNDO 临时回滚段

[日期：2014-05-23] 来源：Linux社区  作者：paulyibinyi [字体：]

Oracle 12C 新特性 Temporary UNDO  可以减少存储在undo表空间的生成量和重做日志的生成
 
[oracle@db12c ~]$ sqlplus / as sysdba

SQL*Plus: Release 12.1.0.1.0 Production on Mon Apr 28 14:18:21 2014

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to:
 Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
 With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options
 
SQL> create global temporary table test as select * from dba_objects where 1=0;

Table created.

SQL> alter session set temp_undo_enabled=false;

Session altered.

SQL> set autotrace traceonly statistics
 SQL>
SQL> insert into test select * from dba_objects;

19397 rows created.

Statistics
 ----------------------------------------------------------
          83  recursive calls
        1690  db block gets
        2621  consistent gets
          5  physical reads
      121876  redo size
        855  bytes sent via SQL*Net to client
        842  bytes received via SQL*Net from client
          3  SQL*Net roundtrips to/from client
          3  sorts (memory)
          0  sorts (disk)
      19397  rows processed

SQL> update test set object_name=lower(object_name);

19397 rows updated.

Statistics
 ----------------------------------------------------------
          6  recursive calls
        615  db block gets
        375  consistent gets
          0  physical reads
    1310712  redo size
        857  bytes sent via SQL*Net to client
        846  bytes received via SQL*Net from client
          3  SQL*Net roundtrips to/from client
          1  sorts (memory)
          0  sorts (disk)
      19397  rows processed

SQL> conn / as sysdba
 Connected.
 SQL>  alter session set temp_undo_enabled=true
  2  ;

Session altered.

SQL> set autotrace traceonly statistics
 SQL>
SQL>
SQL> insert into test select * from dba_objects;

19397 rows created.

Statistics
 ----------------------------------------------------------
          5  recursive calls
        1695  db block gets
        2517  consistent gets
          0  physical reads
        280  redo size
        844  bytes sent via SQL*Net to client
        842  bytes received via SQL*Net from client
          3  SQL*Net roundtrips to/from client
          1  sorts (memory)
          0  sorts (disk)
      19397  rows processed

SQL> update test set object_name=lower(object_name);

19397 rows updated.

Statistics
 ----------------------------------------------------------
          2  recursive calls
      22237  db block gets
        827  consistent gets
          0  physical reads
          0  redo size
        855  bytes sent via SQL*Net to client
        846  bytes received via SQL*Net from client
          3  SQL*Net roundtrips to/from client
          1  sorts (memory)
          0  sorts (disk)
      19397  rows processed

SQL>

调整Oracle回滚的速度

Oracle 回滚(ROLLBACK)和撤销(UNDO)

OCP知识点讲解 之 Undo回滚基础知识

Oracle事务 行级锁 保存点 回滚 提交

Oracle基本步骤前滚和回滚

Oracle 回滚演示 rollback演示

本文永久更新链接地址：

0

Oracle 数据库版本对应的PSU和补丁号码

Oracle 11gR2 grid 集群资源设置跟随集群自动启动

相关资讯       Oracle 12c新特性  Oracle回滚段 

Oracle 12C 新特性  (05月23日)

Oracle GoldenGate 12c 新特性   (04月08日)

图片资讯      

本文评论 　　查看全部评论 (0)

评论声明

最新资讯

本周热门