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DB Block Gets & Consistent Gets.
DB Block Gets. Number of times a CURRENT block was requested. Current mode blocks are retrieved as they exist right now, not in a consistent read fashion. Normally, blocks retrieved for a query are re...
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SCN的Broadcast-On-Commit和Lamport算法
这几天我有一个客户的数据库出现了这样的情况，在一个3节点的RAC上，其中一个节点上修改的数据，马上在另外一个节点上查，发现有千分之5左右的数据没有更新，要过一会才能查到正确的结果。这造成了应用软件的业务逻...
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parallel opration & Distributed Transaction Restrictions
Distributed Transaction RestrictionsA DML operation cannot be parallelized if it is in a distributed transaction or if the DML or the query operation is against a remote object.Examples of Distribut...
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parallel dml & referential integrity constraints
lists all of the parallel operations that are possible on tables that are involved in referential integrity constraints. Table 21-1 Referential Integrity Restrictions DML StatementIssu...
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Restrictions on parallel DML
parallel DML (including direct-path INSERT):Intra-partition parallelism for UPDATE, MERGE, and DELETE operations require that the COMPATIBLE initialization parameter be set to 9.2 or greater. INSER...
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Space Management for Parallel DDL
When creating a table or index in parallel, each parallel execution server uses the values in the STORAGE clause of the CREATE statement to create temporary segments to store the rows. Therefore, a ta...
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local extent management tablespace分配方式
dump segment header Map Header:: next 0x00000000 #extents: 23 obj#: 69335 flag: 0x10000000 Inc # 0 Extent Map ----------------...
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aix检查参数设置
利用lsattr -Elsys0 检查maxuproc, minpout, maxpout等参数的大小。maxuproc为每个用户的最大进程数,通常如果系统运行DB2或ORACLE是应将maxuproc调整，Default：128、调整到500，maxuproc增加可...
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Oracle Automatic Shared Memory Management
Note: There is an advisory on using bitmap free lists (ASMM). ASMM (AMM) and dynamic memory management has measurable overhead for resize operations, and some shop may want to disabl...
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Creating an Oracle Database
http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/create.htm#i1008816 Specifying the Shared Pool SizeThe SHARED_POOL_SIZE initialization parameter is a dynamic parameter t...
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动态SQL中hint是否失效
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - ProdPL/SQL Release 10.2.0.3.0 - ProductionCORE 10.2.0.3.0 ProductionTNS for 32-bit Windows: ...
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latch (Understanding the spin statistics)
The latch statistics in the V$LATCH family of views record a get whenever aprocess acquires a latch in willing-to-wait mode. If the process fails to get thelatch without spinning, a miss is recorded. ...
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constraint states
constraint states includes:ENABLE ensures that all incoming data conforms to the constraintDISABLE allows incoming data, regardless of whether it conforms to the constraintVALIDATE ensures th...
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关于procedure的lock和pin
procedure在执行过程中出现的lock和pinselect KGLNAOBJ,KGLNAOWN,KGLHDPMD,KGLHDLMD from x$kglob where KGLHDPMD>0;KGLNAOBJ &nb...
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Automatic Statistics Gathering
在Oracle10g中引入的优化器统计信息（Optimizer Statistics）自动收集，是一个看上去很不错的功能，但是在实际应用中却往往没有起到相应的效果，甚至在某些系统中我们会建议禁用这个功能。阐述一些该功能的相关知识...
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RAC Connection Redirected To Wrong Host/IP ORA-12545
Doc ID: Note:364855.1 Type: PROBLEM Last Revision Date: 23-APR-2007 Status: PUBLISHED In this Document Symptoms Cause Solution References-------...
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圣斗士星矢243年前的圣战详细介绍
1743年的上代黄金圣斗士 白羊座-史昂 金牛座-白杨 双子座-薛安 巨蟹座-妖 狮子座-艾文斯 处女座-假面 天秤座-童虎 天蝎座-翔 射手座-月华 摩羯座-艾沙 水瓶座-施恩 双鱼座-穆沙 据说上界的双鱼座黄金圣斗士...
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ddl和library cache lock
1、ddl操作过程中会阻塞select操作，并会产生library cache lock等待事件2、ddl操作实际上就是对系统表做dml操作，library cache lock其实就是在dml系统表过程中对row的x lock3、ddl操作和普通dml操作的区别在于，...
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oracle10g AWR
Oracle10G自动工作负荷储存库(AWR)在oracle10G中引进了两个新的进程:mmon和mmnl，其中MMON承担了大部分的工作。以用来从SGA中直接收集统计数据。这些数据都存储在SYSAUX表空间中，并且以WRM$_* 和 WRH$_*的格式命名...
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Memory Configuration and Use
Calculating the Buffer Cache Hit RatioSELECT NAME, VALUE FROM V$SYSSTATWHERE NAME IN ('session logical reads','physical reads', 'physical reads direct','physical reads direct (lob)')...
