Author: mac

To change an init.ora parameter, follow these steps. Open the file called init<database_name>.ora. For example, if the database is called oraprod, then the file would be called initoraprod.ora. The file can be in a variety of places, but almost always somewhere in a subdirectory of the Oracle Installation directory on the server (also known as…

Improve DBWR Throughput To improve DBWR’s throughput, consider the following: Disk capabilities and setup (stripe size, speed, controllers etc…) Using raw devices instead of File System files — depending on their efficiency on your system. Spreading database file across drives and controllers Using Async IO if supported If asynch IO is not possible, using multiple…

The session waits for the lock handle of a global lock request on the distributed file system (DFS). It is most common in a parallel server situation.   Solutions During a period of wait, use the following SQL statement to retrieve the name of the lock and the mode of the lock request: select chr(bitand(p1,-16777216)/16777215)…

Average number of milliseconds waiting for the “log file sync” event, indicating commit times for this database.   Solutions If this is high, review solutions presented in the help file for “log file sync” in the wait time data.

Key compressed indexes are a way to index a low cardinality column without talking up as much space storing the repetitive values. Please view the Oracle Manuals for a full description on implementing compressed indexes.   Benefits Fewer index leaf blocks need to be read since more rows fit into fewer blocks Insert statements are…

The terms “high cardinality” and “low cardinality” are frequently used when discussing table columns. A high cardinality column means that a column has many unique values. For example, a primary key column is a high cardinality column since each value is, by definition, unique. A low cardinality column is the opposite. For example, a column…

Solution By itself, the buffer cache hit ratio is not very meaningful except for databases with undersized data buffer cache (db_cache_size parameter). Oracle provides the data buffer cache advisory utility v$db_cache_advice for assistance with sizing.

show parameter power alter system set asm_power_limit=0; alter diskgroup MACLEAN add FAILGROUP FailgroupA disk ‘/asmdisks/asmdiskA28’; alter diskgroup MACLEAN add FAILGROUP FailgroupA disk ‘/asmdisks/asmdiskA27’; alter diskgroup MACLEAN add FAILGROUP FailgroupA disk ‘/asmdisks/asmdiskA26’; alter diskgroup MACLEAN add FAILGROUP FailgroupA disk ‘/asmdisks/asmdiskA25’; alter diskgroup MACLEAN add FAILGROUP FailgroupA disk ‘/asmdisks/asmdiskA24’; alter diskgroup MACLEAN add FAILGROUP FailgroupA disk ‘/asmdisks/asmdiskA23’;…

Overview of setup and configuration Oracle Enterprise Edition 11gR2. 11.2.0.1.0Linux RH5NetBackup 6.5.5 Identical environments: Identical versions of Oracle. Same ORACLE_HOME and ORACLE_BASE. The archive log directory is defined to be the Flash Recovery Area: You know the DBID. Control file autobackup feature enabled with the default format. NetBackup MML considerations Restoring from tape using the…

ProcDump与Procexp一样是Windows平台上的内部调试工具，Procexp采用图形界面体现系统整体及个别进程的性能信息，而ProcDump则与我们在Unix平台上使用的性能分析工具类似使用CLI命令行界面。 Procdump目前的版本号为3.04，可以从其Homepage上下载到该工具，该监控软件由Mark Russinovich开发，是一款Free Software。其官方介绍如下: ProcDump is a command-line utility whose primary purpose is monitoring an application for CPU spikes and generating crash dumps during a spike that an administrator or developer can use to determine the cause of the spike. ProcDump also includes hung window monitoring (using the same definition of a window hang that…