In this post, I will demonstrate dynamic remastering of the resources in RAC . In RAC, every data block is mastered by an instance. Mastering a block simply means that master instance keeps track of the state of the block until the next reconfigurati…

RAC环境中,每个数据块都被一个instance所管控(mastered),管控数据块的instance被称作主实例(master instance).管控数据块就是说主实例(master instance)会一直跟踪数据块的状态,直到下一次重新配置事件发生,比如实例重启或其它原因.   Hash to the master 数据库根据数据块范围来管控数据块.比如,第10号数据文件的block 1到block128范围内的数据块被instance 1所管控,block 129到block 256…

oracle的events,是我们在做自己的软件系统时可以借鉴的 Oracle 11g trace eventsORA-10001: control file crash event1ORA-10002: control file crash event2ORA-10003: control file crash event3ORA-10004: block recovery testing - internal errorORA-10005: trace latch operations fo…

In this post, I will give a list of all undocumented parameters in Oracle 12.1.0.1c. Here is a query to see all the parameters (documented and undocumented) which contain the string you enter when prompted: – Enter name of the parameter when prompted…

In this post, I will give a list of all undocumented parameters in Oracle 11g. Here is a query to see all the parameters (documented and undocumented) which contain the string you enter when prompted: – Enter name of the parameter when prompted SET l…

  Definitions A trace file is a file that contains diagnostic data used to investigate problems. Also, trace files can provide guidance for tuning applications or an instance.   Types of Trace Files Each server and background process can periodically…

cache fusion  .   grd  .  drm   .   gcs  .   ges cache fusion  1.RAC是一个数据库执行在多个实例上.通过DLM(Distributed Lock Management):分布式锁管理器 来解决并发问题.RAC各个节点间的共享资源,为了保证每一个节点訪问数据的一致性.所以须要使用DLM来协调各个实例间的资源竞争訪问. 这个DLM在RAC中就叫Cache Fusion. 2.在cache Fusion 中,每一个数据块都被映射成Cac…

select * from DBA_CONS_COLUMNS ; ---Information about accessible columns in constraint definitions select * from DBA_LOG_GROUP_COLUMNS ; ---Information about columns in log group definitions select * from DBA_LOBS ; ---Description of LOBs contained i…

今天看书时看到了关于RAC中SCN的问题,为了进一步搞清楚其内部原理和机制,对该问题进行了广泛的查阅和搜索,遗憾的是,可以参考的资料很少,网上大部分是人云亦云的帖子,其中,详细介绍其内部原理和机制的资料更是几乎没有,现将一些有参考价值的资料片段在下面贴出,以供本人和同行参考. 1.Achieving Read Consistency One of the main characteristics of the Oracle database is the ability to simultane…

Cluster的日志体系 Cluster的日志体系: Oracle cluster不像数据库那样,具有丰富的视图.工具可以用来辅助诊断,他的日志和trace文件时唯一的选择.但不想oracle只有alert日志和集中trace文件,oraclecluster的日志体系比较复杂. 4:11g R2RAC 日志 $GRID_HOME/log/: 每个节点上ORACLE集群件以及ASM存储跟踪和诊断日志文件的主目录 $GRID_HOME/log/<hostname>/: 包含本节点上oracle集群…