Oracle Database Tuning ADDM
ADDM (Automatic Database Diagnostic Monitor) implements the Oracle performance method and analyzes statistics to provide automatic diagnosis of major performance problems. Because ADDM can significantly shorten the time required to improve the performance of a system, it is one of the most used performance tuning tools of Oracle database.
1. Run some operations on your database instance.
First, start your database instance and do the database operations (select, update, delete...) which will be optimized. e.g. run a script to make some queries in database:
sh run.sh -r rdf1mm-performance -t p -f p3.txt
2. Login to EM
Login to Database EM home page (https://:5500/em), click Performance tab.
3. Run ADDM
Click Button "Run ADDM Now", and click "Yes" on the confirmation page. After a while, we will see the ADDM analysis page.
Database Activity chart shows the database activity during the ADDM analysis period.
In the ADDM Performance Analysis table, ADDM findings are listed in descending order, from highest to least impact. The Informational Findings section lists areas that have no performance impact and are for information only.
4. Implement ADDM recommendations
Click the ADDM findings that has the impact on performance. e.g. Top SQL Statements.
The Category column displays the category of recommendation. The Benefit column displays the estimated benefit of implementing the recommendation.
If we click "Run Advisor Now", SQL tuning advisor will give us some recommendations on how to tune the SQLs.
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begin
sys.dbms_job.submit(job => :job,
what => 'check_err;',
......
在利用NETWORK_LINK方式导出的时候，出现了这个错误。
详细错误信息如下：
bash-3.00$ expdp yangtk/yangtk directory=d_temp dumpfile=jiangsu.dp network_link=test113 logfile=jiangsu.log tables=cat_org
Export: Release11.1.0.6.0 - 64bit Production on星期二, 16 9月, 2008 17:08:22
Copyright (c) 2003, 2007, ......
Checking kernel parameters
Checking for semmsl=250; found semmsl=250. Passed
Checking for semmns=32000; found semmns=32000. Passed
Checking for semopm=100; found semopm=32. Failed <<<<
Checking for semmni=128; found semmni=128.&nb ......
oracle从9i开始支持一种新的数据类型---- xmltype，用于存储和管理xml数据，并提供了很多的functions，用来直接读取xml文档和管理节点。下面将介绍xmltype的一些基本使用。
1.建立含有xmltype数据类型的表
create table abc (id number,xmldoc sys.xmltype);
声明xmltype型字段用:sys.xmltype
2.向带有xmltype类型的表 ......
oracle常用经典SQL查询
常用SQL查询：
1、查看表空间的名称及大小
select t.tablespace_name, round(sum(bytes/(1024*1024)),0) ts_size
from dba_tablespaces t, dba_data_files d
where t.tablespace_name = d.tablespace_name
group by t.tablespace_name;
2、查看表空间物理文件的名称 ......
