11g

Optimizer in Oracle 11g by wwf.

April 11, 2013 11g, advanced tech, oracle No comments

By wwf from ebay COC about Optimizer in Oracle 11g.

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Can not purge obsolete cursor in 11.2.0.3

November 28, 2012 11g, maintain, oracle No comments

11.2.0.3中Oracle引入了_cursor_obsolete_threshold隐藏参数,默认为100,表示一个parent cursor最多可以有100个child cursor;如果SQL需要第101个child cursor,则将该parent cursor and its 100 c[……]

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Oracle Direct NFS Performance

November 23, 2012 11g, Architect, oracle, software 1 comment

在Oracle 11g中引入了Direct Network File System(Oracle Direct NFS)的新特性,通过一个打包在Oracle内核中的NFS client来提高使用NFS时的性能,DNFS同样适用于RAC等高可用场景。

DIRECT NFS CLIENT OV[……]

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Incremental Statistics for Partitioned Tables in 11g

November 8, 2012 11g, oracle No comments

这篇文档是我们前leader wwf 写的分析文档,指出了incremental statistic针对partition table 的一些用法,并且指出了一些bug,看不了slideshare的TX可以直接下载Inc_Stat_For_PT.doc

11gR2 rac install ASM terminating the instance due to error 481

October 16, 2012 11g, oracle, RAC No comments

一套新上线的RAC系统(redhat 5.8 RAC 11.2.0.3) 安装过程中跑GI root.sh时抛出error 481错误:

CRS-2672: Attempting to start 'ora.asm' on 'ptdb1'
CRS-50[......]

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11g Smart Flash Cache

August 30, 2012 11g, oracle, RAC No comments

整理一篇关于11g smart flash cache 的文章,vmcd

我们来做一下演示 采用FusionIO SLC 160G

[oracle@db-41 ~]$ ls -l /dev/fi[......]

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11.2.0.2 EXPDP 遭遇 ORA-4031

July 16, 2012 11g, maintain, oracle No comments

一套oracle 11.2.0.2 数据仓库系统使用expdp导出数据时 进程hang 死 使用kill -9命令杀掉之后 database一直没有释放latch 通过下面的日志可以发现 pmon已经发现 ospid=15038的process dead 但是无法clean 进程在为 “fixed[……]

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11g DEFAULT_MAINTENANCE_PLAN 总结

June 18, 2012 11g, oracle No comments

查看数据仓库的awr报告发现以下问题 顺便总结一下之前碰到的一类问题

CPU Time (s)Executions CPU per Exec (s)%TotalElapsed Time (s)%CPU%IO SQL IdSQL ModuleSQL Text
13,664.[……]

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11g 密码延迟登陆导致 library cache lock

May 24, 2012 11g, oracle No comments

前阵子刚写过11g密码延迟登陆的新特性,11g oracle在登陆密码输入错误时候不会立刻中断这个连接而会递增等待时间,这有可能在失败登陆N次以后达到一个很长的阀值(10s),从而导致session 大量积压导致问题的严重化,今天就碰到了问题,PMS team在转换密钥的时候出现了问题,应用一直狂连[……]

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11G New feature: Failed Logon Delays

April 27, 2012 11g, oracle 4 comments

在pub上看到一个不错的帖子 oracle 11g password delay

对这个特性 做如下说明

Failed Logon Delays

A hacker may attempt a brute force hack to break into your Oracle D[……]

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