What are key tasks for an Oracle DBA on daily basis?
A user issues the below query, 1. select * from table1 lock table at the same time DBA is trying to modify this table table1 using alter command, will he able to do that or not?
DDL lock are exclusive locks. It shared the data. Means anyone can select data from same table.
there dba can break the lock given to table.
but in real time, no dba has the right to break the lock given by the user
Why use materialized view instead of a table
If materialized view contains the actual data and has to be re-created every time the original table data is changed and we intent to refresh the data in the view.Then what is the actual use of materialized view, why can't we create another table by itself by running the same query ?
Materialized view is useful in replication and data warehousing environment where every time data extracting and data loading from another sites,databases. Materialized view also useful for maintaining complex queries because it uses query rewrite feature.
Common problems while taking backups
What are the common problems while taking backups? What are the necessary steps to take backup on to tapes and disks in real time?
For a cold backup :shutdown oracle first and then proceed the cold(offline) back up. once you shutdown the oracle database insert the external tape/disk.pls ensure the tape/disk is in good condition. ...
Some Common issues with Backup. If you are taking backup from no-archive log: then your database doesn't bring down due to some processes are running. If you are taking hot backup then may be newly ...
Dear friend, it is not RAP but it is WRAP. Using this utility of Oracle, we can hide our PL/SQL code from user.
What is difference between spfile and init.Ora file???
spfile provides dynamic mean of maintaining your initialization parameters.
Sp file is static and p file is dynamic
Which process writes data from data files to database buffer cache?
Server process
Data always copied in buffer cache from data file by only Server Process not DBWR.
What are the advantages of views
Exactly View is logical identity.Oracle only stores definition of View in metadata. Using view, we can hide some columns of tables from users, we can hide original table name from user. Using view we can perform complex query in single statement.
Assume that the dba is modifying a tables and the same time developer want to use that database a then dba can provide him the view for that tables.
Code
What are the components of logical database structure of Oracle database
Logical Structure of Oracle is following.
Tablespace =>Schema => Segments => Extent => Oracle Block. (Remember Oracle block is smallest logical unit).
the logical components of database are tablespaces, segments, extents, datablocks. datablock is the smallest unit of oracle I/0.
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Daily Tasks of DBA are following. 1. Disk Space checking for all databases, tablespaces, archive log destinations, dump destinations, and backup destinations. 2. All backup successfully finished or n...
1.Connectivity: Make sure each database is available and accessible both by logging in via user applications, as well as running test scripts. 2.Backups: Check database and log backups, archiving an...