Order of temporary disk space uses by Sort stage

The Sort stage uses temporary disk space when performing a sort. It looks in the following locations, in the
following order, for this temporary space.

1. Scratch disks in the disk pool sort (you can create these pools in the configuration file).
2. Scratch disks in the default disk pool (scratch disks are included here by default).

Interview Questions : Unix/Linux : Part-8

1. Display all the files in current directory sorted by size?
ls -l | grep '^-' | awk '{print $5,$9}' |sort -n|awk '{print $2}'


2. Write a command to search for the file 'map' in the current directory?
find -name map -type f

3. How to display the first 10 characters from each line of a file?
cut -c -10 filename

4. Write a command to remove the first number on all lines that start with "@"?
sed '\,^@, s/[0-9][0-9]*//' < filename

Interview Questions : DataWareHouse - Part6

What is BUS Schema?
BUS Schema is composed of a master suite of confirmed dimension and standardized definition if facts.

What are the methodologies of Data Warehousing?
Every company has methodology of their own. However, to name a few SDLC Methodology, AIM methodology is standard used.

Interview Questions : DataWareHouse - Part 5

How Many different schemas or DW Models can be used in Siebel Analytics. I know Only STAR and SNOW FLAKE and any other model that can be used?
Integrated schema design is also used to define an integrated schema design we have to define the following concepts

► Fact constellation
► Act less fact table
► Onformed dimension

A: A fact constellation is the process of joining two or more fact tables

B: A fact table with out any facts is known as fact less fact table

C:A dimension which is re useful and fixed is known as conformed dimensionA dimension, which is, shared with multiple fact tables known as conformed dimension

What is an error log table in Informatica occurs and how to maintain it in mapping?
Error Log in Informatica is a one of output file created by Informatica Server while running the session for error messages. It is created in Informatica home directory.

Oracle Interview Questions - Part-4

76. What is the OPTIMAL parameter?
It is used to set the optimal length of a rollback segment.

77. What is the functionality of SYSTEM table space?
To manage the database level transactions such as modifications of the data dictionary table that record information about the free space usage.

78. How will you create multiple rollback segments in a database?
- Create a database, which implicitly creates a SYSTEM rollback segment in a SYSTEM tablespace.
- Create a second rollback segment name R0 in the SYSTEM tablespace.
- Make new rollback segment available (after shutdown, modify init.ora file and start database)
- Create other tablespaces (RBS) for rollback segments.
- Deactivate rollback segment R0 and activate the newly created rollback segments.

List of strong points for InterView :-)

Most of time we stuck when Interviewer ask about our Strong Point, there are lot of reasons behind this ;-) anyways, Here sharing some words which can help you to decide. Pick which suits you but know them ;-) before using.


• A activating, adapting, administering, analyzing information, arranging, advising

• B budgeting, building teams, briefing, balancing,

• C communicating, controlling, co-ordinating, creating, checking, counseling, compiling, coaching

• D deciding, detailing, developing people, directing, devising, discovering, data input

Interview Questions : DataWareHouse - Part 4

What are the types of Synonyms?
There are two types of Synonyms Private and Public

What is a Redo Log?
The set of Redo Log files YSDATE, UID, USER or USERENV SQL functions, or the pseudo columns LEVEL or ROWNUM.

What is an Index Segment?
Each Index has an Index segment that stores all of its data.

Explain the relationship among Database, Table space and Data file?
Each databases logically divided into one or more table spaces one or more data files are explicitly created for each table space.

Interview Questions : DataStage - self-3

100    If 1st and 8th record is duplicate then which will be skipped? Can you configure it?
101    How do you import and export datastage jobs? What is the file extension? (See each component while importing and exporting).
102    How do you rate yourself in DataStage?
103    Explain DataStage Architecture?
104    What is repository? What are the repository items?
105    What is difference between routine and transform?
106    When you write the routines?

Interview Questions : DataStage - self-2

48    Why can’t we use sequential file as a lookup?
49    What is data warehouse?
50    What is ‘Star-Schema’?
51    What is ‘Snowflake-Schema’?
52    What is difference between Star-Schema and Snowflake-Schema?
53    What is mean by surrogate key?
54    What is ‘Conformed Dimension’?

Interview Questions : DataStage - self-1

Sharing some collection of InterView Questions. Try these to rank your knowledge :-)


1    Types of Stages in DS? Explain with Examples
2    What are active stages and passive stages?
3    Can you filter data in hashed file? (No)
4    Difference between sequential and hashed file?
5    How do you populate time dimension?
6    Can we use target hashed file as lookup? (Yes)
7    What is Merge Stage?
8    What is Job Sequencer?
9    What are stages in sequences?
10    How do you pass parameters?
11    What parameters you used in your project?

Interview Questions : DataWareHouse - Part 3

 What is data warehousing?
"In computing, a data warehouse (DW) is a database used for reporting and analysis. The data stored in the warehouse is uploaded from the operational systems. The data may pass through an operational data store for additional operations before it is used in the DW for reporting.
A data warehouse maintains its functions in three layers: staging, integration, and access.
Staging is used to store raw data for use by developers. The integration layer is used to integrate data and to have a level of abstraction from users. The access layer is for getting data out for users.
The term Data Warehouse was coined by Bill Inmon in 1990, which he defined in the following way:

Interview Questions : DataStage - Part 2

For more : Visit HERE

What is the importance of Surrogate Key in Data warehousing?

Ans : Surrogate Key is a Primary Key for a Dimension table. Most importance of using it is independent of underlying database. i.e Surrogate Key is not affected by the changes going on with a database

What does a Config File in parallel extender consist of?

Ans: Config file consists of the following.
a) Number of Processes or Nodes.
b) Actual Disk Storage Location.

Interview Questions : DataWareHouse - Part 2

For more : Visit HERE




What is real time data-warehousing?

Data warehousing captures business activity data. Real-time data warehousing captures business activity data as it occurs. As soon as the business activity is complete and there is data about it, the completed activity data flows into the data warehouse and becomes available instantly.

What are conformed dimensions?

Conformed dimensions mean the exact same thing with every possible fact table to which they are joined. They are common to the cubes.

What is conformed fact?

Conformed dimensions are the dimensions which can be used across multiple Data Marts in combination with multiple facts tables accordingly.

Oracle Interview Questions - Part-3

51. What is a database instance? Explain.
A database instance (Server) is a set of memory structure and background processes that access a set of database files. The processes can be shared by all of the users. The memory structure that is used to store the most queried data from database. This helps up to improve database performance by decreasing the amount of I/O performed against data file.

52. What is Parallel Server?
Multiple instances accessing the same database (only in multi-CPU environments)

Interview Questions : DataWareHouse - Part-1

What is Data Warehousing?
A data warehouse is the main repository of an organization’s historical data, its corporate memory. It contains the raw material for management’s decision support system. The critical factor leading to the use of a data warehouse is that a data analyst can perform complex queries and analysis, such as data mining, on the information without slowing down the operational systems. Data warehousing collection of data designed to support management decision making. Data warehouses contain a wide variety of data that present a coherent picture of business conditions at a single point in time. It is a repository of integrated information, available for queries and analysis.

Oracle Interview Questions - Part-2

26. What is hash cluster?
A row is stored in a hash cluster based on the result of applying a hash function to the row’s cluster key value. All rows with the same hash key value are stores together on disk.

27. When can hash cluster used?
Hash clusters are better choice when a table is often queried with equality queries. For such queries the specified cluster key value is hashed. The resulting hash key value points directly to the area on disk that stores the specified rows.

Oracle Interview Questions - Part-1

1. What are the components of physical database structure of Oracle database?
Oracle database is comprised of three types of files. One or more datafiles, two or more redo log files, and one or more control files.

2. What are the components of logical database structure of Oracle database?
There are tablespaces and database’s schema objects.

3. What is a tablespace?
A database is divided into Logical Storage Unit called tablespaces. A tablespace is used to grouped related logical structures together.

Interview Questions : Unix/Linux : Part-7

For more : visit here

1. How to display the processes that were run by your user name ?
ps -aef | grep <user_name>

2. Write a command to display all the files recursively with path under current directory?
find . -depth -print

Interview Questions : Unix/Linux : Part-6

1.       How do you write the contents of 3 files into a single file?

cat file1 file2 file3 > file

2.       How to display the fields in a text file in reverse order?

awk 'BEGIN {ORS=""} { for(i=NF;i>0;i--) print $i," "; print "\n"}' filename

3.       Write a command to find the sum of bytes (size of file) of all files in a directory.

ls -l | grep '^-'| awk 'BEGIN {sum=0} {sum = sum + $5} END {print sum}'

Interview Questions : DataStage - Part 1

How did you handle reject data?
Ans: Typically a Reject-link is defined and the rejected data is loaded back into data warehouse. So Reject link has to be defined every Output link you wish to collect rejected data. Rejected data is typically bad data like duplicates of Primary keys or null-rows where data is expected.

If worked with DS6.0 and latest versions what are Link-Partitioner and Link-Collector used for? 
Ans: Link Partitioner - Used for partitioning the data.
Link Collector - Used for collecting the partitioned data.