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ASE Server Performance
What will you do when the ASE server's performance is bad?
rajat_dua
- Mar 2nd, 2009
Bad performance" is not a very meaningful term, so you'll need to get a more objective diagnosis first. Find out (i) what such a complaint is based on (clearly increasing response times or ju...
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Accessing Dual Table
Explain Dual table. Is any data internally stored in dual table. Lot of users are accessing select sysdate from dual and they getting some millisecond differences. If we execute SELECT SYSDATE FROM EMP; what error will we get. Why?
abdulraheem_ar
- Aug 5th, 2008
Dual is a system owned table created during database creation. Dual table consist of a single column and a single row with value xWe will not get any error if we execute select sysdate from scott.emp?...
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Increase %LIKE Operator Performance
How do you increase the performance of %LIKE operator?
ravinder.pathania
- Oct 6th, 2008
The wildcard char % can be placed in one of three ways: %searchwordhere% searchwordhere% %searchwordhere The searchwordhere% is the fastest because it can use an index if one is specified on that ...
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Estimate SGA Size
How to estimate the size of SGA?
rajat_dua
- Mar 2nd, 2009
SQL> show sgaTotal System Global Area 167772160 bytesFixed Size 1247900 bytesVariable Size 58721636 bytesDatabase Buffers 104857600 bytesRedo Buffers 2945024 bytes
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Troubleshoot SQL * Plus
If the SQL * Plus hangs for a long time, what is the reason?
gurbux
- Jul 19th, 2010
SQL statement is taking long time to retrieve results from database.See which statement is taking longtime by running SELECT * FROM sqltext; or SELECT * from v$session_longops;
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Restricted Mode Memory Gap
How to check to memory gap once the SGA is started in Restricted mode?
sonaligujral1
- Aug 7th, 2010
No memory gap would occur whether database is started in open or restricted mode.
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Execute Analyze Table Command
In which situation whether peak time or off peak time you will execute the ANALYZE TABLE command. Why?
harisivati
- Jul 13th, 2008
Gathering statistics can be very resource intensive for the server so avoid peak workload times to gather stale stats or Analyze Table .
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Replication Server
Explain how will you setup Replication Server & sync it?
vijaykaushik
- Dec 31st, 2008
Replication server can be setup using many ways1)Using Oracle Streams2)Using Advanced replication 3)Using Mviews.Each has their own mechanism to sync data. Regards,Vijay Kaushik
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Tuning Indicators
What tuning indicators can one use?
prahlad_786
- Jun 25th, 2010
The following high-level tuning indicators can be used to establish if a database is performing optimally or not: • Buffer Cache Hit Ratio Formula: Hit Ratio = (Logical Reads - Physical Read...
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Import Export Utilities
How does one use the import/export utilities?
nafees
- Jul 22nd, 2008
Logical Backup using export utility works as an alternative backup method.we can export from one user and import into another within the same database.we can export from one database and import into a...
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Monitor and Modify Data during Loading
How to monitor how fast a table is imported? How to modify data as it loads into the database?
Ramshankardba
- Jan 17th, 2009
Use below script to monitor how speed import is happening.SELECT SUBSTR(sql_text, INSTR(sql_text,'INTO "'),30) table_name, rows_processed, ROUND( (sysdate-TO_DATE(first_load_time,'yyyy-mm-dd hh24:mi:s...
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Stacktrace Server Error Log
What should you do when you find a stacktrace in the server errorlog?
Lokesh M
- Dec 7th, 2011
When the server crashes, it generates core dump. If value of orclsdumpflag is set to 0, then the server will also attempt to leave a stack trace. The location for the stack trace is: ORACLE_INSTANC...
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Load Data into Multiple Tables
How to load data into multiple tables at once?
vijaykaushik
- Dec 31st, 2008
You can use SQL loader to do this. Using the When condition in SQL Loader control file this is possible.
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Temp DB Full
What do you do when tempdb is full?
hari_97us
- Nov 26th, 2009
You need to clean up the space and add more space in order to prevent this error in future.
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Recover Database
There are 100 datafiles, numbered from 1 to 100. File number 10 is deleted and it has 500 MB of data. The database is working in No-Archive log mode. How can the database be recovered?
vijaykaushik
- Dec 31st, 2008
This can be easily done but you will loose the data if you don't restore from backup.If you have a backup of datafiles and controlfile then restore them.If you don't have the backup then you n...
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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 ?
doc123
- Mar 23rd, 2012
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.
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Why and how the deadlock situation arises
If one user is already updating the table and it has a lock, the other user cannot access the table to update. then why and how the deadlock situation arises ?please explain with example.
prahlad_786
- Jun 25th, 2010
When 2 different DML executed on the same resource then it leads to dead lock.Example:If a resource locked by user A and it also need resource which is locked by user B. B also need a ...
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Physical Standby Database
Outline the steps required for physical standby database creation?
nafees
- Jul 21st, 2008
Hi all,IT IS POSSIBLE WITH THE HELP OF DATA GUARD.To create a physical standby database ,the standby databse should be in MRM(Managed recovery mode)Let we proceed with an example, let ...
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Database Designing and Modeling
What are the differences between database designing and database modeling?
ramu541
- Sep 12th, 2008
Effective database design can help the development team reduce overall development time and costs. Undertaking the process of database design and creating a data model helps the team better understand...
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Differentiate file using filename
Three users at a time giving the following command: alter database backup controlfile to trace; How can you differentiate the file using the filename itself?
baala
- Aug 11th, 2008
When you issue the command "alter database backup controlfile to trace ; " a trace file will be created in the user_dump destination.The default name of the trace file would look something similar to ...
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