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使用9.2.0.1的export导出工具 导出 10.2.0.1的数据库中的数据，确实有问题。exp-00003 ORACLE文档提供了相关资料：使用9.2.0.5以下的export导出工具，导出9.2.0.5或以上版本的数据库的数据，的确会导致报错exp-00003. 具体的bug内容，ORACLE并没有公开。 解决方法： 确实就是您在文档中所查到的方法。我发给您的文档中，“Workaround 2”就是描述了这样的方法。 [@more@]Doc ID: 274076.1Type: PROBLEM Modified Date : 04-JUL-2008Status: PUBLISHEDThe information in this document applies to: Oracle Server - Enterprise Edition -

Five RabbitsFive rabbits were hiding,In the woods one day,1-2-3-4-5 jumped out,and then they ran away.[@more@]

Eensy Weensy spiderThe eensy weensy spider went up the water spout.Down came the rain and washed the spider out.Out came the sun and dried up all the rain.And the eensy weensy spider went up the water spout again.The eensy weensy spider went up the water spout.Down came the rain and washed the spider out.Out came the sun and dried up all the rain.And the eensy weensy spider went up the water spout again. [@more@]

Doc ID: 340951.1Type: PROBLEM Modified Date : 06-MAY-2007Status: MODERATEDIn this Document Symptoms Changes Cause Solution ReferencesThis document is being delivered to you via Oracle Support's Rapid Visibility (RaV) process, and therefore has not been subject to an independent technical review.Applies to: Oracle Enterprise Manager - Version: 10.1.0.2This problem can occur on any platform.SymptomsTrying to connect a 10G database via 9i OEM standalone console.- Try connect with 'SYSTEM' user

10.2:Enabling Tracing for Java-Based Tools and Utilities in Oracle Real Application ClustersAll Java-based tools and utilities that are available in Oracle RAC are invoked by executing scripts of the same name as the tool or utility. This includes the Cluster Verification Utility (CVU), Database Configuration Assistant (DBCA), the Net Configuration Assistant (NETCA), the Virtual Internet Protocol Configuration Assistant (VIPCA), Server Control (SRVCTL), and the Global Services Daemon (GSD). For

1. OPTIMIZER_INDEX_COST_ADJ:调整优化器在选择访问路径时更趋于使用索引还是使用全表扫描.缺省值100(即100%,百分比系数)表示按照常规方式计算索引访问路径.若为其他值,表示在计算得出的常规索引代价基础上乘以该百分比系数,使得其索引代价更少或更多.如:设置为50,表示索引访问代价是正常索引代价的50%,使得系统更偏向于使用索引.在OLTP环境,可以设定此值小于100.2. OPTIMIZER_INDEX_CACHING[@more@]设置非0值,将使得CBO更倾向于使用嵌套循环(Nested loop)和IN-LIST.定义了优化器假定索引块在内存中的百分比.设置此参数为高值,导致优化器更

Migrating Data to a Different Operating SystemWhen using the Database Upgrade Assistant or when performing a manual upgrade, you cannot migrate data in a database on one operating system to a database on another operating system. For example, you cannot migrate data in an Oracle9i database on Solaris to an Oracle Database 10g database on Windows 2000 using the Database Upgrade Assistant.If you need to migrate Oracle Database to a different operating system, the best practice is to follow these s

in oracle database 10.2,by default, Oracle enables traces for DBCA and the Database Upgrade Assistant (DBUA). For the CVU, GSDCTL, SRVCTL, and VIPCA, you can set the SRVM_TRACE environment variable to TRUE to make Oracle generate traces.[@more@]

数据文件丢失, 没有备份, 拥有文件创建以来的全部归档,使用RMAN恢复, 报错RMAN-06102: no channel to restore a backup or copy of log thread 1 seq 726 scn 1757142927; 使用sqlplus恢复, 执行 'Alter Database recover datafile ' Fails with ORA-279总结: RMAN备份没有使用catalog, controlfile默认保留7天的备份/归档信息,v$archived_log没有记录足够多的归档信息, 所以报RMAN-06102, 需要通过CATALOG命令注册.SQLPLUS 执行 'Alter Database recover datafile ' Fails with ORA-279 因为9.2.0.6版本使用这个命令不能自动执行recover.

Atempo公司的TimeNevigator是第三方的备份管理软件.声称:"带有Oracle模块的Time Navigator通过提供Oracle数据库高性能在线备份和恢复来提供增强了的应用软件实用性而不影响终端用户。该应用软件能提供一个Oracle数据库对象的逻辑视图,提供先进的诊断工具并实现小部分或完整的恢复。" 其工程师告知针对ORACLE数据库有两种备份方式,一种是RMAN调用,一种是数据文件读取方式,不通过RMAN. RMAN备份大家都理解,对于直接读取数据文件的方式其实就是置表空间为BEGIN BACKUP和END BACKUP状态,并无其他神奇之处. [@more@]对于直接读取数据

客户端连接间歇性失败，报错ORA-12519OERR: ORA-12519 TNS:no appropriate service handler found[@more@]Error: ORA-12519 / TNS-12519Text: TNS:no appropriate service handler found ---------------------------------------------------------------------------Cause: the listener could not find any available service handlers that are appropriate for the client connection. Action: run "lsnrctl services" to ensure that the instance(s) have registered with the listener, and are accepting connections.

locally managed tablespace 使用bitmap来管理tablespace extent. bitmap存储在每个文件的文件头中。每个extent占据bitmap中的一个bit.管理extent的方式:autoextent(由oracle来自动管理)，和uniform(通过表级存储参数) [@more@]A tablespace that manages its own extents maintains a bitmap in each datafile to keep track of the free or used status of blocks in that datafile. Each bit in the bitmap corresponds to a group of blocks. When an extent is allocated or freed for reuse, Oracle changes the bitmap values to s

V$fixed_table中可以查到所有的X$TABLE的名字。[@more@]可以用如下脚本进行基本查看X$ 表的基本信息:SELECT NAME x$table_name FROM v$fixed_table WHERE NAME LIKE 'X$%' ORDER BY NAME; 也可以通过 Unix 的 strings 命令抽取 oracle 命令里的 X$ 表的信息。$ strings $ORACLE_HOME/bin/oracle >xtable.sql 然后查看 xtables.sql 文件的内容。一些特定的缩写的含义X$KS - Kernel Services X$KSL - Kernel Service Latch X$KC - Kernel Cache X$KQ - Kernel Query X$KQ - Kernel Generic X$LE - Lock Element X$

oracle 统计数据存放于：user_tables, user_tab_columns, user_tab_cols(including virtual columns), user_tab_histograms.计算selectivity / cardnality 非常重要。提供user_tab_columns.low_value和user_tab_columns.high_value的转换函数。 字符串做范围查找时，需要根据编码转换成数字，提供此函数cbo_char_value。[@more@]自定义函数：VALUE_TO_DATEVALUE_TO_NUMBERVALUE_TO_VARCHAR2cbo_char_valueSQL> desc t1 ?? ????? ?? ----------------------------------------- -------- --------

ORACLE RAC 用于INTERCONNECT 的内网卡的物理连接方式的选择：采用交换机连接或是网线直连。itpub讨论中谈到直连的弊端，一旦一个节点机的内网卡出现故障，oracle从OS得到两个节点的网卡状态都是不正常的，因而会导致两个实例都宕掉。下面是讨论过程：[@more@]biti说：从理论上来推测 这里面要注意区分 使用switch 和 直连 的情况：如果使用交换机，拔掉a的，b 会知道自己是活的，a 知道自己出问题了。那么b能提供服务，a将不能提供服务，应该选择down掉是合理的选择。如果是直连，可能出现 brain split，两个节点都不能正常提供服务。但k

使用rman nocatalog 备份到带库, varitas 备份软件的备份全库脚本：oracle@tjgM85:/usr/openv/netbackup/ext/db_ext/oracle/samples/rman> more hot_database_backup.sh [@more@]#!/bin/sh# $Header: hot_database_backup.sh,v 1.9 2002/02/06 16:48:56 lstrub Stab $##bcpyrght#***************************************************************************#* $VRTScprght: Copyright 1993 - 2002 VERITAS Software Corporation, All Rights Reserved $ *#***********************************************************************

oracle按照standard formula计算cost，当对于number/date类型字段做range scan, oracle都可以得到比较准确的selectivity. （之所以说是比较准确而非正确，因为虽然我们的数字、日期实际是离散的，但oracle optimizer认为是连续的，所以我们想查询2002-12-30－2003-01-05在2000-2004年（共1827天）中的selectivity，期望是7/1827，但oracle并不会这样计算）。[@more@]若以number类型存储年月日yyyymmdd 计算结果为：standard fomula:selectivity=(required range) / (high value - low value) + 2/num_distinct=(20030105-20021230)/(20041