Informatica ETL Interview Questions Solutions

2/19/2010 No Comment

Dataware Housing Informatica Interview Questions and Solutions

Please use the comment section to answer, if you find more relevant answers to these questions.

Explain what is the difference between static cache and dynamic cache in Informatica?
In dynamic cache, when we try to insert a new row it checks the lookup cache to see if it exists, if not inserts it into the target as well as the cache but in case of static cache the new row is written only in the target and not the lookup cache. The lookup cache remains static and does not change during the session but incase of dynamic cache the server inserts, updates in the cache during session.

Explain how can we join two tables without joiner or SQL override?
We can join the tables using lookup tansformation and by making a cartesian product.

What are pre-session and post-session options in Informatica?
These are shell commands that Informatica server performs before running the session. We should have the sufficient permission and privileges to run these options in Informatica.

Explain how do we copy mapping in Informatica?
There are 3 steps to copy mapping are mentioned below: 

1.) First, open navigator window 
2.) Open the mapping in repository 
3.) Click copy

Can you tell me what are the tasks done by Informatica server?
 The most important tasks done by Informatica server are cited below 

a.) Managing the sessions 
b.) Running the workflows 
c.) Tuning performance 
d.) Scheduling of sessions and workflows

What do you mean by mapping parameters and mapping variables?
 Mapping parameters are parameters which are constant through out the session. They are specified before running the session. Unlike parameters, variables change through out the session.

Explain what is the difference between source qualifier and joiner transformation in Informatica?
We require matching keys in source qualifier which we do not require in joiner transformation.

Explain why do we use partitioning the session in Informatica?
Partitioning achieves the session performance by reducing the time period of reading the source and loading the data into target.

For session partition what are the necessary tasks you have to do?
Configure the session to partition source data. Then proceed on to install the Informatica server on a machine with multiple CPU running on it.

How many number of sessions that you can create in a batch?
  In a batch we can create any number of sessions we want.

Can you tell me when the Informatica server marks that a batch is failed?
If there is one session configured to “run if previous completes” and that previous session fails.

What is a command that used to run a batch?
pmcmd is used to start a batch and run a batch

What are the different options used to configure the sequential batches?
Two options available are cited below.

  • Run the session only if previous session completes successfully.
  • Always runs the session.
Is it possible to start a session within a batch individually?
: One can start the sessions in this way in the case of sequential batches only. In case of the concurrent batches it is next to impossible to start.
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