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How to handle data curreption for ASM type files?
imran44
- Dec 30th, 2008
The storage array should contain one or more spare disks (often called hot spares). When a physical disk starts to report errors to the monitoring infrastructure, or fails suddenly, the firmware should immediately restore fault tolerance by mirroring the contents of the failed disk onto a spare disk
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Explain about Oracle Statistics parameter in export?
ramanava1
- Feb 22nd, 2008
Export is one of taking backup. In export backup you can specify many parameters in par file or at command line. One of the parameter is statistics=y or n. If you specify y it is going to export statistics generated in the database placed in dump file.
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What is difference between base table and data dictionary views?
kunal1017
- Jan 10th, 2008
HiBase tables are made when the database is created and these tables are stored in data dictionary. these base tables contains the information related to the database.? these tables are own by sys.th...
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How to manager Memory in Oracle Database? How to maximize nos. of user in Oracle Database?
kailasTile
- Dec 17th, 2007
It depends on your requirement, if you want no of users around 300 then you can still achieve that by keeping PGA parameters low. If you are looking for number of users 1000 or even more, you need to go for shared server mode.
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Is VARCHAR2 size optimization worthwhile ?
Hi, I've recently commissioned a hosted system from a developer who has recommended using J2EE and Oracle. Their J2EE system is quite slick and works very well in preproduction. It uses annotations to generate the Oracle tables on the fly during deployment. On examination of the table structures that it's generated though, it's defaulted all of the VARCHAR2 definitions to 255 characters. On asking...
kailasTile
- Dec 18th, 2007
Changing VARCHAR2(255) to precise required width is good table design. Though it will not improve performance as such.
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Index tablespace for a Database
How to assign an index tablespace for a database permanently, so that whatever indexes we are creating in the database, should automatically goes to that tablespace i.e. we neednot supply the tablespace name during index creation.
kailasTile
- Dec 17th, 2007
There is no such provision in oracle to have default index tablespace. Workaround is- you can have a job which will scan for indexes in other tablespaces and rebuild into desired one.
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What are the fixed memory structures inside the SGA?
rajat_dua
- Mar 3rd, 2009
Part of the SGA contains general information about the state of the database and the instance, which the background processes need to access; this is called the fixed SGA. No user data is stored here....
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Cloning and Standby Databases
What is the difference between Cloning and Standby databases?
rajendra_thanekar
- Jan 2nd, 2008
Cloning is nothing but the copy of your database which can be open in read write mode. The standby database is also a copy of your database which is in standby mode and which is made in sink with prod...
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Installing Oracle9i/10g at unix (RedHat) environment
While Installing Oracle9i/10g at unix (RedHat) environment , which parameter needs to be set at OS level, to login as a sysdba in Oracle for the first time?
skpanuganti
- Feb 8th, 2008
.bash_profile has to set at OS level before connecting to oracle database.
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Difference between failover and switch over servers
kailasTile
- Mar 27th, 2008
Failover: Primary fails and standby is made primary.Switchover: Primary and secondary interchanges the role.Effectively, in both cases, standby becomes primary, main difference is, when failover happe...
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Cost Based Optimizer and Rule Based Optimizer
What is the difference between Cost Based Optimizer and Rule Based Optimizer?(CBO is the default optimizer)
ajay.ocp
- Aug 20th, 2008
In brief the rule-based method means that when executing a query the database must follow certain predefined rules and matter what data is stored in affected database tables. The cost-based method mea...
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Limit and Default size of Tablespace
Can we create as many tablespace as we require. What is the limit? What is the default size of tablespace? (System and User tablespace). Mention name of some tablespace.
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Compression Parameter
You have a database of 2GB. Can you convert the database to 1GB. Which compression parameter will you use?
hemant.agarwal03
- Mar 18th, 2008
COMPRESSION =(METADATA_ONLY | NONE) - This parameter applies from Oracle 10.2. It specifies whether to compress metadata before writing to the dump file set. Compression reduces the amount of disk spa...
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Datafile Size
What is your datafile size? How long it can go? What is the max limit to which you can extend?
hemant.agarwal03
- Mar 18th, 2008
v$datafile data dictionary view will tell us the size of a datafile.to check the number of datafile you can check db_files init parameter. you can also alter this parameter but it will reflect after restartthe database.you can also resize the datafile size.
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Cache Fusion Technology
What is Cache Fusion Technology?
bhuvannpg
- Feb 28th, 2008
Cache Fusion is a new technology that uses a high speed interprocess communication (IPC) interconnect to provide cache to cache transfers of data blocks between instances in a cluster. This eliminates...
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DBMS_meta_data Parameter
DBMS_meta_data. This parameter is very usefull. What you infer from this parameter. What info you will find in that. explain in detail.
hemant.agarwal03
- Mar 12th, 2008
To find the structure of a external table we used this package.syntax is below:SELECT DBMS_METADATA.GET_DDL ('TABLE','<Table Name in CAPS>')||';' FROM DUAL
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Disk (sort) Ratio
The ratio of disk (sort) is high. Is that good or bad? Why? How will you reduce disk sort?
rajendra_thanekar
- Apr 17th, 2008
Hi,Disk(sort)ratio is high is not good.Please set sort_area_retained_size and sort_area_size so that session can sort in max in memory.
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