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2010-12-29

Oracle闩:Cache Buffers chains

Latch cache buffers chains大约是Oracle中child latch数量最多,使用最为频繁的闩锁了。其子闩总数受到初始化参数(8i中的db_block_buffers/4)的影响,Oracle中有大量kernel函数有机会接手持有cache buffer chains latch: col parent_name for a25 col location for a40 ...
#POST 36 MIN READ
2010-12-29

[转]Oracle销售人员普遍腐败?

2004年7月19日,中国上海,Oracle大中华区董事总经理陆纯初带着他的新高管班子集体亮相于Oracle World会场。对于陆纯初治下的Oracle中国公司来说,这是一次集体兴奋。 不过,更需要陆纯初面对的是,Oracle中国公司的问题并没有因此而平息下来,人事变动只是其中一环,更致命的问题在于Oracle中国公司盲目举起直销大旗,多少有兔死狗烹之嫌。尽管陆纯初并不否认合作伙伴...
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2010-12-29

Goldengate OGG常见问题与错误列表

以下列出了OGG一些常见的问题与错误及其解答: Note: 966211.1 How To Resync A Single Table With Minimum Impact To Other Tables' Replication? Note: 966227.1 Troubleshooting TCP/IP Errors In Open Systems Note: 972954.1 What C...
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2010-12-28

如何确定所打Patch是否需要停机

Oracle在11g中提出了online patching(也可以叫做hot patch)的概念,有效减少了因实施one-off patch而导致的系统停机时间。但我们如何得知哪些Patch是可以online apply的,而哪些Patch是必须关闭实例(shutdown instance)后应用的呢? 下面我们就介绍一种简单有效地方法来识别这2种Patch: 1. 从MOS下载所需要的Patch...
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2010-12-27

Merry Christmas Sql Statement

这段Merry christmas的查询来源于Gilles Haro的博客,不过看到的时候已经是27号了,呵呵! with Mx as (select 60 as MaxWidth from dual) select decode (sign(floor(MaxWidth / 2) - rownum), 1, lpad(' ', floor(MaxWidth / 2) - (rownum - 1)...
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2010-12-27

Latches and Tuning:Latches

1. Query the V$FIXED_TABLE to determine the V$ views that provide latch information. a. Execute the following query:> select name from v$fixed_table where name like 'V$LATCH%'; 2. Remember that the...
#POST 13 MIN READ
2010-12-27

Oracle优化器:星型转换

Oracle 8i中引入了星型转换(star transformation)的优化器新特性以便更有效地处理星型查询。星型查询语句多用于基于星型模型设计的数据仓库应用中。星型模型的称谓源于该种模型以图形化表现时看起来形似一颗海星。这颗星的中央会由一个或多个事实表(fact tables)组成,而各个触角上则分布着多个维度表(dimension tables),如下图: 星型转换的基本思路是尽量避免直...
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2010-12-26

Latches and Tuning:Redo Log Buffer and Latches

1. The size of the redo log buffer is determined by the LOG_BUFFER parameter. a. Determine the size of the LOG_BUFFER by executing the following query:> select * from v$sga; b. View the LOG_BUFFER ...
#POST 13 MIN READ
2010-12-26

Latches and Tuning:Buffer Cache

1. The buffer pool is structured into pools; RECYCLE, KEEP, and DEFAULT. Unless otherwise specified at create time or altered, an object will reside in the DEFAULT pool. a. Suppose you have a table th...
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2010-12-26

How to set LOGSOURCE PATHMAP on GoldenGate

Question: the source machine os is solaris ,the mid machine os is linux , the target machine os is solaris,i want extract archive log file and pump trail file to target on mid machine , i check Golden...
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