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Linux命令
1. 修改登录提示符显示用户名，本机名和当前工作目录 export PS1="$LOGNAME@$HOSTNAME:\$PWD:"
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分区表全局索引与本地索引的选择
原文地址：http://www.oraclebuffer.com/general-discussions/which-index-to-choose-global-or-local-index-for-partitioned-table/Introduction:We often deal with Indexes while working on Oracle database tables. We do know, there are different type of indexes like B-Tree, Bitmap, Hash-value, etc, etc....
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分区表索引Global与Local的选择
原文：http://www.oraclebuffer.com/general-discussions/which-index-to-choose-global-or-local-index-for-partitioned-table/Introduction:We often deal with Indexes while working on Oracle database tables. We do know, there are different type of indexes like B-Tree, Bitmap, Hash-value, ...
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使用VMWare Workstation基于Oracle Linux 6安装oracle数据库集群
因为步骤记录在了Word文档中，其中有大量图片，故将文档分享在此1-安装操作系统.docx2-配置虚拟机.docx3-克隆虚拟机.docx4-安装clusterware.doc5-创建数据库.docx安装过程参考：http://willyristanto.blogspot.jp/2014/03/oracle-rac-database-11gr2-on-oel-59.htmlhttps://blogs.oracle.com/askmaclean/entry/%E5...
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RAC安装时碰到的错误
INS-41105 on subnet chosen as public does not match subnet of SCAN VIP.通过修改用于RAC内部通信的网卡的子网掩码解决ifconfig eth3 netmask 255.0.0.0
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CBO的查询转换（谓词推入与子查询展开（Subquery Unnesting））
1. 谓词推入 谓词推入是将外层的相关谓词，推入至内层查询视图当中（View Query Block），使得内层视图可以利用谓词进行索引扫描或者过滤 如： SELECT col1, col2, col3 FROM (select col1, col2, col3 from table_a a union all ...
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突破常识：SQL增加DISTINCT后查询效率反而提高
只要增加了DISTINCT关键字，Oracle就会对随后跟着的所有字段进行排序去重。以前也经常发现由于开发人员对SQL不是很理解，在SELECT列表的20多个字段前面添加了DISTINCT，造成查询的执行异常缓慢，基本上很难在ORA-1555错误出现之前得到查询的结果，甚至有些SQL会产生ORA-7445错误。所以在给开发人员培训的时候还着重介绍了...
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Oracle OCP 1Z0 053 Q175(noarchivelog&alter tablespace backup mode)
175.You are peer reviewing a fellow DBAs backup plan for his NOARCHIVELOG mode database, asshown here:Put the tablespaces in backup mode.Back up the datafiles for all tablespaces.Take the tablespaces out of backup mode.Back up all archived redo logs.Your colleague asks for you to comment on hi...
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Oracle OCP 1Z0 053 Q74(ASM POWER ASM_POWER_LIMIT)
74.Immediately after adding a new disk to or removing an existing disk from an ASM instance, you findthat the performance of the database goes down initially until the time the addition or removal process iscompleted, and then gradually becomes normal.Which two activities would you perform to mai...
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Oracle OCP 1Z0 053 Q709(Recovery Redo log)
709. A database has three online redo log groups with one member each. A redo log member with thestatus ACTICE is damages while the database is running.What is the first step you should take to solve this problem?A.Attempt to Issue a checkpoint.B.Restart the database using the RESETLOGS option....
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Oracle OCP 1Z0 053 Q401(Block Media Recovery)
401.Which of the following are correct about block media recovery? (Choose all that apply.)A. Physical and logical block corruption is recorded automatically in V$DATABASE_BLOCK_CORRUPTION.B. Logical corruptions are repairable by BMR.C. Physical corruptions are repairable by BMR.D. RMAN can use...
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Oracle OCP 1Z0 053 Q648(Flashback)
648.Note the following statements that use flashback technology:1. FLASHBACK TABLE <table> TO SCN <scn>;2. SELECT * FROM <table> AS OF SCN 123456;3. FLASHBACK TABLE <table> TO BEFORE DROP;4. FLASHBACK DATABASE TO TIMESTAMP <timestamp>;5. SELECT * FROM <table> VERSIONS AS OF SCN 123456 AND 12399...
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Oracle OCP 1Z0 053 Q45( ASM-preferred mirror read)
45.What is the advantage of setting the ASM-preferred mirror read for the Stretch cluster configuration?A. It improves resync operations.B. This feature enables much faster file opens.C. It improves performance as fewer extent pointers are needed in the shared pool.D. It improves performance by ...
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Oracle OCP 1Z0 053 Q700(RMAN Duplicate)
700. Which two statements are true about a duplicate database that is created by using the DUPLICATEcommand in RMAN? (Choose two.)A.It is a copy or a subset of the target database.B.It is opened in RESTRICT mode after a duplicating operation.C.It is created by using backups and archived redo log...
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Oracle OCP 1Z0 053 Q677(Flashback Transaction Query)
677.What are the prerequisites for performing flashback transactions? (Choose all that apply)A.Supplemental log must be enabledB.Supplemental log must be enabled for the primary keyC.Undo retention guarantee for the database must be configuredD.”EXECUTE “ permission on the DBMS_FLASHBACK packa...
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Oracle OCP 1Z0 053 Q416
416.To manually configure the SGA components using Oracle Enterprise Manager Memory Advisor, youcan set values for which of the following initialization parameters? (Choose all that apply.)A. DB_CACHE_SIZEB. SHARED_POOL_SIZEC. LARGE_POOL_SIZED. JAVA_POOL_SIZEE. SGA_MAX_SIZEF. SORT_AREA_SIZEA...
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Oracle OCP 1Z0 053 Q52(DB_ULTRA_SAFE)
52.You have the following requirements in relation to the detection of block corruption for your databaseinstance:Check for logical self-consistency of data blocks when modified in memory.Checksums are calculated before and after the block change.Checks are performed for the lost writes to the p...
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Oracle OCP 1Z0 053 Q105(Table Compression)
105.Which statements are true regarding table compression? (Choose all that apply.)A. It saves disk space and reduces memory usage.B. It saves disk space but has no effect on memory usage.C. It incurs extra CPU overhead during DML as well as direct loading operations.D. It incurs extra CPU overh...
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Oracle OCP 1Z0 053 Q410(Workload Capture&Replay)
410.Which of these recommendations should be followed before capturing a workload? (Choose all thatapply.)A. Make sure your replay database has the same structure as the capture database, except without data.B. Make sure the replay and capture databases are similar in data content.C. Perform a c...
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Oracle OCP 1Z0 053 Q538(ASM)
538.Which type of database file is spread across all disks in a disk group?A. All types of files are spread across all disks in the disk group.B. DatafilesC. Redo log filesD. Archived redo log filesE. Control filesAnswer: A参考：http://blog.itpub.net/17013648/viewspace-1312551/
