总排名： 15383

 xzh2000的博客
RSS地址： http://xzh2000.itpub.net/rss/atom/96
共有1篇文章被收藏推荐
收录于2007-07-24
认领 报错 推荐

▶ 如何计算long字段的长度   2008-07-24 00:08

有一个应用，在访问clob时抛出异常如下：FATAL ERROR IN TWO-TASK SERVER: error = 12152*** 2008-07-17 18:28:43.912ksedmp: internal or fatal errorORA-12571: TNS:packet writer... 有一个应用，在访问clob时抛出异常如下：FATAL ERROR IN TWO-TASK SERVER: error = 12152*** 2008-07-17 18:28:43.912ksedmp: internal or fatal errorORA-12571: TNS:packet writer failureRDBMS:9206，查metalink，证实为一个未公开的bug，为了挠过该bug，将clob类型的字段改成long类型，结果访问还是有问题，当长度超过一定的长度时，proc程序就只能读取前4000个字符，因为应用已经发布，修改代码已经来不急。查看了一下long字段的内容，发现文字内容很少的，大部分都是html的格式代码，只需要找出长度超过4000的记录，去掉该部分html代...

▶ Stream在11gR1的新特征   2008-07-10 21:47

相对于10gR2而言，11gR1中stream的新功能更是令人期待，比如：同步捕获（synchronous capture）功能，已经脱离日志挖掘的范畴；stream性能顾问（stream performance... 相对于10gR2而言，11gR1中stream的新功能更是令人期待，比如：同步捕获（synchronous capture）功能，已经脱离日志挖掘的范畴；stream性能顾问（stream performance advisor）可以识别stream拓扑中的瓶颈、分离与合并stream的目标站点(对于复杂的stream环境可以提高其可用性及可维护性)，跟踪LCRs的状态等、支持透明数据加密等、比较与同步共享的数据库对象（当复制环境中名称相关的表数据不一致时，可以用dbms_comparison包来同步）。。。同步捕获（synchronous capture）同步捕获是11gR1中推出捕获dml的新功能，它利于内部机制去捕获指定...

▶ Parallel Query Wait Events   2008-04-17 14:51

SCOPE & APPLICATION-------------------This is intended as a reference for anyone involved in database tuning. At the moment we consider the following PX wait events as idle: - "PX Idle Wait"- "PX Deq: Execution Msg"- "PX Deq: Table Q Normal"- "PX Deq Credit: send blkd"- "PX Deq: Execute Reply"- "PX Deq Credit: need buffer"- "PX Deq: Signal ACK"- "PX Deque wait"In 9i statspack does not... SCOPE & APPLICATION-------------------This is intended as a reference for anyone involved in database tuning. At the moment we consider the following PX wait events as idle: - "PX Idle Wait"- "PX Deq: Execution Msg"- "PX Deq: Table Q Normal"- "PX Deq Credit: send blkd"- "PX Deq: Execute Reply"- "PX Deq Credit: need buffer"- "PX Deq: Signal ACK"- "PX Deque wait"In 9i statspack does not filter out all idle PX wait event inthe Top 5 wait event section. So it can happen that you seea PX idle wait ev...

▶ Recovery is repairing media corrupt block   2008-04-17 02:50

在dataguard环境中，经常发现standby库的pxxx进程的trace文件中有这样的信息，查了metalink，官方的解释：并不是bug或者错误，而是因为在primary database执行了不可恢复的操作导致的，解决的办法特简单，在primary database上执行以下操作：alter database force logging;可以用以下的脚本查看那些数据文件有问题：SELECT... 在dataguard环境中，经常发现standby库的pxxx进程的trace文件中有这样的信息，查了metalink，官方的解释：并不是bug或者错误，而是因为在primary database执行了不可恢复的操作导致的，解决的办法特简单，在primary database上执行以下操作：alter database force logging;可以用以下的脚本查看那些数据文件有问题：SELECT name, unrecoverable_change# , unrecoverable_time FROM v$datafile where UNRECOVERABLE_CHANGE# > 0 order by 1;

▶ ASM INSTANCE & Shared Pool (ORA-4031)   2008-03-27 03:40

The setting for the SHARED_POOL_SIZE parameter determines the amount of memory required to manage the instance. The setting for this parameter is also used to determine the amount of space that is allocated for extent storage. The default value for this parameter is suitable for most ASM environments. 1) For 32-bit environments 32 MB is the default and minimum requirement for an ASM instance,... The setting for the SHARED_POOL_SIZE parameter determines the amount of memory required to manage the instance. The setting for this parameter is also used to determine the amount of space that is allocated for extent storage. The default value for this parameter is suitable for most ASM environments. 1) For 32-bit environments 32 MB is the default and minimum requirement for an ASM instance, but 48 MB is recommended. 2) On 64-bit platforms 88 MB are required for an ASM instance, recommended val...