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redo 相关的events及涉及到结构与参数
<WaitEvent:log_file_sequential_read> <WaitEvent:log_file_single_write> <WaitEvent:log_file_parallel_write> <WaitEvent:log_file_space_switch> <WaitEvent:log_file_switch_check...
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Tuning RAC and using parallel features(6)
RAC waits events ad interconnect statisticsThe RAC events are listed next in the report if you are running RAC (multiple instances). As stated earlier, you need to run STATSPACK or AWR Report for eac...
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Tuning RAC and using parallel features(5)
RAC Cluster interconnect performance The most complex aspect of RAC tuning involves monitoring and the subsequent tuning of process associated with the Global Services Directory(GSD) . T...
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Tuning RAC and using parallel features(4)
Cache Fusion and Resource Coordination Since each node in Real Application Cluster has its own memory(cache) that is not shared with other nodes, RAC must coordination the buffer ca...
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Tuning RAC and using parallel features(3)
Global Cache Resources(GCS) and Global Enqueue Services(GES)The key role is played by GCS and GES (which are basically RAC processes). GCS ensures a single system image of the data even though the da...
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Tuning RAC and using parallel features(2)
Internal Workings of the Oracle RAC System In 9i RAC, we no longer talk about DLM,PCM, non-PCM, Lock Monitor,etc.Most of the functionality is replaced in Oracle 10g or performed in the name of ...
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Tuning RAC and Using Parallel Features(1)
Cluster interconnect If a block of data is on one node and the user asks for it on another node, oracle uses cache fusion to pass one block through the interconnect to the other n...
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cursor_sharing_exact hints的使用
cursor_sharing_exact hints的使用主要当cursor_sharing=similar或者force的时候使用比较方便,以下就是为cursor_sharing=similar的时候的一个sqltrace.可以看到当使用hints cursor_sharing_exact后,Misses in li...
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使用临时表来优化的存储过程
使用临时表来优化的存储过程对于海量数据作检索的时候，通常会由于巨大的数据量，造成大量的排序和过滤。SELECT TECHNOLOGY_RRN, TECHNOLOGY_ID, &nb...
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EXPLAIN PLAN WHEN USING PARTITIONS
EXPLAIN PLAN WHEN USING PARTITIONSTable partitions yield different outputs for their EXPLAIN PLANs (as shown in the following listing).Here, we create a table with three partitions and a parti...
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Using dbms_monitor
Using dbms_monitor SQL> select sid,serial# ,username from v$session; SID SERIAL# USERNAME---------- ---------- -------------------...
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使用dbms_profiler包辅助pl/sql优化
d使用dbms_profiler包辅助pl/sql优化SQL> conn / as sysdbaConnected.首先就是创建以下对象：SQL> @$ORACLE_HOME/rdbms/admin/profload.sqlPackage created.Grant succeeded.Synonym created.Library created.Packag...
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LOADS、INVALIDATIONS and PARSE_CALLS
dLOADS、INVALIDATIONS and PARSE_CALLSSQL> select * from v$version;BANNER----------------------------------------------------------------Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Pr...
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Troubleshooting Guide to high version_counts
Greate jobAuthor: James Cremonini 1. Troubleshooting Summary 2. Introduction: What is shared SQL ? 3. Diagnostics: How do I see the versions and why they are not shared ? 4. Documentation: What do the...
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oracle9i RAC性能调整(一)
rac turning工作中,一直在使用RAC环境的数据库,当然我是以9i见多.对于RAC的一些性能的调整,一直是一个比较大的问题.这里将部分自己的经验以及来自其他参考的文献写下这样的笔记.以方便自己,也方便别人.我们知道,在RA...
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bitmap的锁机制
dbitmap的锁机制bitmap index的索引的机制是比较特殊的，因为bitmap index entry 包含了一段rowid范围，因此当这个rowid对应的行被更新，就会出现锁情况了。我们来看一个例子，为了模拟需要打开三个sessionSQL> crea...
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free buffer waits
今天五一啊,相信大多数人都在准备出行了.我就比较惨了,今天凌晨4点被电话叫醒,客户报数据库慢.这下可好.通过QQ远程连接到客户那里.然后telenet. 唉!那速度......不过还好了.折腾了半天终于还是登上去了.总比跑一趟现...
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How can I tune a tablescan?
Author's name: Jonathan LewisThis particular example is typical of the generic case. We have a query like the following on a 40GB table, but the index is ‘not selective’:select {list of columns}...
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监控索引使用
d首先要保证在系统比较空闲的时间做：注意：以下所有操作都是以sys身份1、如要监控tm_im_work_data表中的全部索引，首先通过以下sql查出该表所有的索引以及索引所对于的列。select b.owner,b.index_name,b.index_typ...
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RAC Diagnostics Script
from metalink:This script is broken up into different SQL statements that can be used individually. Each SQL statement adds information to help in debugging an RAC hang/severe performance scenerio. ...
