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创建index之前如何确定其大小

March 8, 2012 Internals, maintain, oracle 1 comment structure

昨天看了roger的一篇文章，如何在创建index 之前估算它的大小，这里有一种更简单的方法实现：

主要思路就是采用了dbms_space.create_index_cost这个包

–create a testing table named t
SQL> create table t as select * from dba_objects;

Table created.

SQL> declare
begin
for i in 1..10 loop
insert /*+ APPEND */ into t select * from t;
commit;[……]

11gR2 RAC Rebootless Node Fencing

March 6, 2012 Internals, oracle, RAC No comments RAC

Rebootless Node Fencing

In versions before 11.2.0.2 Oracle Clusterware tried to prevent a split-brain with a fast reboot (better: reset) of the server(s) without waiting for ongoing I/O operations or synchronization of the file systems. This mechanism has been changed in version 11.2.0.2 (fi[……]

Scripts:sess_uncommited_transactions.sql

March 2, 2012 maintain, oracle No comments scripts

This script is monitoring sessions that are not commited :

— |—————————————————————————-|
— | Copyright (c) 1998-2012 Jeffrey M. Hunter. All rights reserved. |
— |————————————————————–[……]

Cloning an Oracle Home

March 2, 2012 migration, oracle 1 comment database migrate

Cloning an Oracle Home

Cloning an Oracle home involves creating a copy of the Oracle home and then configuring it for a new environment. If you are performing multiple Oracle Database installations, then you may want to use this method to create each Oracle home, because copying files fro[……]

11.2.0.3 datapump got ORA-38500

February 23, 2012 maintain, oracle No comments 11g

从10.2.0.5的库导入一张表的增量数据到11.2.0.3 impdp报出如下错误,对比两边表结构一致，tablespace有剩余空间报错如下：

[oracle@localhost ~]$ impdp \’\/ as sysdba \’ directory=pump dumpfile=so.dmp TABLE_EXISTS_ACTION=append

Import: Release 11.2.0.3.0 – Production on Thu Feb 23 09:44:49 2012

Fractured blocks when Rman backup is running

February 20, 2012 backup, oracle, replication No comments structure

系统alert在主库出现下面错误 OS为linux 5.5

Stopping background process CJQ0
Sat Feb 11 03:41:07 2012
Hex dump of (file 9, block 561424) in trace file /data/oracle/diag/rdbms/yhdstd/yhddb1/trace/yhddb1_ora_11327.trc
Corrupt block relative dba: 0x02489110 (file 9, block 561424)
Fractured block found durin[……]

招聘：1号店招聘ORACLE DBA

February 17, 2012 system No comments

新的一年到了,DBA TEAM准备扩充一下,主要环境是ORACLE(RAC+单实例+DG)+ MYSQL 后面还要涉及到MYSQL的高可用架构实施,ORACLE方面今年也会有一些架构变更,总体而言今年是很有挑战的一年,希望挑战与激情的同学可以来试一试,同时也欢迎大牛的加入

Location:Shanghai

简历发送到ylouis83@gmail.com

vmcd
2012-02-17[……]

11g new feature Index Invisible

February 15, 2012 11g, oracle No comments 11g new feature

11g为我们提供了Index Invisible特性，使用这个特性可以轻松的将index置为不可用状态，对比之前的将索引置为unusable
最大的改进是，当index设置为unusable时，索引将不再随着表数据的更新而更新，导致如果重新使用index 需要rebuild等操作
这对大型的OLTP系统是极大的挑战，而invisible则不然

下面做个测试：

SQL> create table t_test1 as select * from all_objects;

Table created.

SQL> create index t_te[……]