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Memory Architecture
Database Buffer CacheThe database buffer cache is the portion of the SGA that holds copies of data blocks read from datafiles. All user processes concurrently connected to the instance share access t...
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IBM系列AIX小型机巡检项目及流程参考
IBM系列AIX小型机巡检项目及流程参考1、机器型号# uname -uMIBM,7029-6E3 IBM,01100550A2、检查系统硬件设备故障灯是否有亮3、系统错误报告# errpt -d H -T PERM //硬件的错误报告IDENTIFIER TIMESTAMP&n...
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Fast Connection Failover
http://download.oracle.com/docs/cd/B19306_01/java.102/b14355/fstconfo.htm#CEGGDDFJ
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RAC TAF
Overview of Transparent Application Failover (TAF) The TAF function is controlled by processes external to the Oracle Database 10g RAC cluster control. The cl...
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Viewing Histograms
Viewing HistogramsColumn statistics may be stored as histograms. These histograms provide accurate estimates of the distribution of column data. Histograms provide improved selectivity estimates in t...
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关于大表的带条件分批删除
Oracle9i Enterprise Edition Release 9.2.0.7.0 - 64bit Production要执行的操作是delete dbcrmadm.dCustGrpUserShould where acct_month='200901'；应用反映操作很慢。select count(*) from dbcrmadm.dCustGrpUs...
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rman backup algorithm
Algorithm RulesThe basic backup algorithm follows several important tenets when creating backup sets. Eachallocated channel that performs work in the backup job—that is, each channel that is not idle...
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ORADEBUG
一、 概要首先看看helpSQL> oradebug helpHELP [command]  ...
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the TWO PHASE COMMIT
(01) The global coordinator initiates and commits the distributed transaction. During execution of the SQL statements within the transaction, the defini...
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字符集总结
1、NLS_LANG指定客户端使用何种字符集显示数据库的字符2、插入数据库时，NLS_LANG指定insert时用的字符集，当直接在客户端的sqlplus中insert时候不管你实际使用何种字符集，都认为是NLS_LANG指定的字符集，因为sqlp...
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Viewing Index Information
The following views display information about indexes:ViewDescriptionDBA_INDEXES ALL_INDEXES USER_INDEXESDBA view describes indexes on all tables in the database. ALL view describes index...
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IMP过程中对象丢失
imp过程中丢失了两个表三个索引，再日志中出现了 " ALTER TABLE "TPHS_PHS_INFACE" MODIFY ("DEAL_FLAG" DEFAULT '0'" " ALTER TABLE "TPHS_SHT_MGR" MODIFY ("HL_FLAG_ID" DEFAULT 0"丢失右括号的报错，这是...
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Predicate Selectivity
Selectivity~~~~~~~~~~~文档 ID: 72539.1 68992.1Selectivity is a measure of the proportion of a row source retrieved by application of a particular predicate or combination of predicates.Within th...
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dump
事件说明例子Event 10013 - Monitor Transaction Recovery在Startup时跟踪事务恢复ALTER SESSION SET EVENTS '10013 trace name context forever, level 1';Event 10015 - Dump Undo Segment Headers-在...
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row cache lock与seq竞争
row cache lockoracle将数据字典存于sga内的行高速缓冲区（dictionary cache)内。行高速缓冲区位于共享池区域，可通过如下命令进行确认。sql> select pool,name,bytes from v$sgastatwhere name='row cache';想要修...
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Avoiding ORA-1555 Errors
Avoiding ORA-1555 Errors One of the most vexing problems that Oracle DBAs around the world face every day is this: ORA-1555: snapshot too old: rollback segment number 9 with name "R07" too small To...
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Parallel Execution Tuning
Parallel execution improves processing for:Queries requiring large table scans, joins, or partitioned index scansCreation of large indexesCreation of large tables (including materialized views)...
