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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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Instance of Database Problem
Tell me any instance when your database encountered any problem. How you dealt with that problem.
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Properties of Database Isolation
Describe four properties of database isolation. In which situation lock contention will happen. What is transaction lock?
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Simple and Advance Replication
What is simple replication and advance replication? What is the difference between simple replication and advance replication? How can we do simple replication?
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A day as a DBA
How you spend a day as a DBA. Explain DBA activities in detail.
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How can the problem be resolved if a SYSDBA, forgets his password for logging into enterprise manager?
mhans
- Feb 25th, 2008
1. Always you should have one more user activated as SYSDBA and this is achieved by using orapw utility2. If there is just one SYS user then on unix platform, login as ORACLE user (DBA group)3. sqlplus '/ as sysdba'alter user sys identified by 'xyz' ;This would change SYS pwd
senthilora
- Sep 24th, 2007
I think there are 2 ways to do that.1. Login as SYSTEM and change the SYS password by using ALTER USER.2. Recreate the password file using orapwd and set remote_password_file=exclusive and then restart the instance.
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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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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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What is the difference between materialized view and snapshots
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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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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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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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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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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 is directory naming in oracle9i ?
pradeesh04
- Dec 7th, 2007
Oracle Net Services use a centralized directory server as one of the primary methods for storage of connect identifiers. Clients configured directory usage can use the connect identifiers in the...
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What is the difference between Pctused and PctFree?
dinesh1909
- Nov 19th, 2007
Consider 8K block size. The total bytes 8 x 1024 = 8196 bytesEach block requires approximately 117 bytes for the header. Please note that the header size varies depending upon the block size. The tota...
C.Ramesh
- Nov 16th, 2007
PCT USERD - The Percentage of Minimum space user for insertion of New Row data. The value determines when the block gets into the FREELISTS structurePCTFREE - The Percentage of Space reserved for future updation of existing dataC.Ramesh
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What is a deadlock ? Explain .
Two processes wating to update the rows of a table which are locked by the other process then deadlock arises. In a database environment this will often happen because of not issuing proper row lock commands. Poor design of front-end application may cause this situation and the performance of server will reduce drastically. These locks...
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What is a latch?
Latches are low level serialization mechanisms used to protect shared data structures in the SGA. The implementation of latches is operating system dependent, particularly in regard to whether a process will wait for a latch and for how long.A latch is a type of a lock that can be very quickly acquired and freed. Latches are typically used to prevent more than one process from executing the same piece...
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Latches vs Enqueues
Enqueues are another type of locking mechanism used in Oracle. An enqueue is a more sophisticated mechanism which permits several concurrent processes to have varying degree of sharing of "known" resources. Any object which can be concurrently used, can be protected with enqueues. A good example is of locks on tables. We allow varying levels of sharing on tables e.g. two processes can lock a table...
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What is difference between Logical Standby Database and Physical Standby database?
The primary functional difference between logical and physical standby database setups is that logical standby permits you to add additional objects (tables, indexes, etc) to the database, while physical standby is always an exact structural duplicate of the master database. The downside, though, is that logical standby is based on newer technologies (logical standby is new in Oracle 9.2) and tends...
Oracle DBA Interview Questions
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