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The techniques described here can be used when initial diagnosis of a database performance problem suggests that further investigation needs to concentrate on finding and tuning the most resource intensive SQL statements according to specific criteria, e.g.[@more@]Applies to: Oracle Server - Enterprise Edition - Version: 9.2.0.1 to 11.1.0.7 - Release: 9.2 to 11.1Information in this document applies to any platform.PurposeThis article provides guidance on how to identify the most resource intensi

Information to help diagnose log file sync can be obtained using the script. found in Note 1064487.1.（metalink artic)[@more@]Information to help diagnose log file sync can be obtained using the script. found in Note 1064487.1.A: Log file sync waits occur when sessions wait for redo data to be written to disk. Typically this is caused by slow writes or committing too frequently in the application. Checking the "user commits" section in the AWR report can reveal if the issue is related

备份恢复测试方案一， 首先先把lnxh_v2的表空间中的业务数据表迁移出另外的表空间metarnet。二， 可以通过可传输的表空间把源数据库表空间导入到目标数据库表空间。[@more@]备份恢复测试方案一， 首先先把lnxh_v2的表空间中的业务数据表迁移出另外的表空间metarnet。二， 可以通过可传输的表空间把源数据库表空间导入到目标数据库表空间。三， 对于业务运营产生的新数据通过expdp导出主库metarnet，生成dmp文件，再通过impdp的追加数据方式把dmp文件导入复制库。迁移lnxh_v2表空间中的业务数据到metarnet表空间1，create tablespace metar

一． 分析：RMAN并不支持客户端连接服务器进行备份，所以仍然需要在服务器上使用RMAN备份，客户要求备份至异地；[@more@]一． 分析：RMAN并不支持客户端连接服务器进行备份，所以仍然需要在服务器上使用RMAN备份，客户要求备份至异地； 二． 环境： 1. 两台win2003 Enterprise edition：主机名si_vm_w2k3，ip:192.168.2.204;备机名PC2 ip:192.168.2.205 2. 在si_vm_w2k3上和PC2上同时安装oracle 10.2.0.1.0; 3. ORACLE_HOME=C:oracleproduct10.2.0db_1.ORADATA=C:oracleproduct10.2.0oradatalichao; 三． 操作步骤： 1,

cost =blevel +ceiling(leaf_blocks * effective index selectivity) +ceiling(clustering_factor * effective table selectivity)[@more@]cost =blevel +ceiling(leaf_blocks * effective index selectivity) +ceiling(clustering_factor * effective table selectivity)Historically it has been common practice to say that a good index has a low clustering_factor, and a badindex has a high clustering_factor.There is obviously a degree of truth in this comment, especially in the light of what the clustering_factorre

接触Oracle两年时间了，因为爱好一不小心坚持了下来，转眼间大学即将毕业，我也要踏上专职DBA的道路了，萌生了写blog的念头，把自己学习的过程和解决问题的过程记录下来，算是作为一个技术人对自己的小交代吧。希望和网络上的朋友共同学习和提高。[@more@]