Informatica Interview Questions & Answers
Informatica Interview Questions and Answers
Dear Readers, Welcome to Informatica Interview Questions have been designed specially to get you acquainted with the nature of questions you may encounter during your Job interview for the subject of Informatica. These Informatica Questions are very important for campus placement test and job interviews. As per my experience good interviewers hardly plan to ask any particular questions during your Job interview and these model questions are asked in the online technical test and interview of many IT companies.
1. What is a Repository and difference between repository database and repository service
Repository is metadata which means it has data about the data(objects). It stores the data regarding the Informatica objects .For eg: We have a folder say “Folder1” and 3 mappings has been created within it, so all the information regarding all objects in mapping and the folder will be stored in repository database in forms of tables.
Repsoitory database is a database which contains all the metadata whereas the repository service is nothing but a service which runs on repository database and provides its services.
OPB_Mapping: This table contains all the mapping names.
2. What is a code page
Code page contains encoding to specify characters in a set of one or more languages.
Eg: If you have Malaysian or Chinese character in your source data then you have to choose the appropriate code page for these characters else you’ll see square boxes once the data is loaded and processed as Informatica will not be able to understand those characters.
3. What is resilience time?
Resilience time is the time defined in Informatica to wait before it lose the connection on a network failure.
Eg: If your resilience time is 180 sec and the network goes down so Informatica will wait for 180 sec and if network is established in between, the connection will be established. If the network is not up within 180 sec so the unsaved data will be lost and the client will be disconnected from the domain or repository
4. What is a node in Informatica?
A node in Informatica is logical representation of a machine.
5. What is data movement mode in Informatica and difference between them?
The data movement mode depends on whether Informatica server will process single byte or multi-byte character data set.
There are two data movement modes in Informatica:
I. Unicode: It allows two bytes for each character and uses the additional byte for each non ASCII character(Such as Malaysian characters)
II. ASCII: It holds the data in a single byte.
6. How do you migrate data from one environment to another.
There are generally three types of methodology used for data migration in Informatica
I. Copy Paste: Copy the folder or object in one repository and click on the destination repository and paste it(This can be done with pmrep command aslo)
II. Import and Export: Exporting the object definition in xml file and then importing it to the destination folder or repository
III. Deployment group: While migrating objects in bulk the deployment group concept comes into picture. Create a deployment group, add then folders and object to it and then migrate the deployment group.
7. What is an Integration service in Informatica?
Integrations service is a application service in Informatica which run the workflows and session. It tells the Informatica server how to flow the data from source to target.
Analogy: Integration service is like a carrier truck which carries the goods (data) from one place to other.
8. Pmrep and pmcmd command
pmrep and pmcmd commands are the command line interface to perform Informatica related task. These command s are used most in form of scripts. Pmrep is used for all repository related tasks. Pmcmd is used for Informatica monitor and server related tasks
Eg: pmrep connect –r Repository_name –d Domain_name –n Username –x password
The above command connects to repository. Once connected you can create a folder in repository by below command
Pmrep createfolder –f Foldername –o OwnerName
Some of the pmcmd commands:
I. Startworkflow
II. Stopworkflow
III. Waitworkflow
IV. Recoverworkflow
V. Scheduleworkflow
VI. Startask
VII. Stoptask
9. How to start a workflow using pmcmd command
Pmcmd startworkflow [ folder]
[ taskInstancePath []]
[ paramfile]
[ localparamfile]
[ OSProfile] [-wait|-nowait]
[ runInsName] workflow
10. Creating a folder using pmrep command
Pmrep createfolder –f Foldername –o OwnerName
11. What is deployment group
A deployment group is a global object that consists of versioned objects from one or more folders. You use a deployment group to copy the versioned objects to another folder or repository. You can use a deployment group when you want to copy some, but not all, of the objects in a folder. You can also use a deployment group to copy objects from multiple folders
12. How to go to the older version for a mapping.
There is no direct approach to revert back a mapping to previous version however it can be achieved by the procedure defined below.
Right click on the mapping->version-View history
All the versions will be listed out. Select the version you want to revert back to and export or save its definition in local drive. Rename the last version with new name and then import the file.
13. What is DR strategy for Informatica project?
A backup node can be defined for all nodes and services, so incase if the primary node goes down the backup node can take over the control.
Note: You should have the license to create a backup node
14. How to open an older version of an object in the workspace
To open an older version of an object in the workspace:
I. In the workspace or Navigator, select the object and click Versioning > View History.
II. Select the version you want to view in the workspace and click Tools > Open in Workspace.
Note: An older version of an object is read-only, and the version number appears as a prefix before the object name. You can simultaneously view multiple versions of a non-composite object in the workspace
15. How would you join a node to the already existing domain?
joining a node to an existing domain can be archived while installing Informatica.
Eg: Server is on machine1 and the new node is on machine2. Then go to machine2-Open Installer->join node to domain while configuring domain and provide the existing domain details.
16. Is it possible to create multiple domains on a single Informatica server?
Yes it is possible to create multiple nodes on same Informatica server
17. While migrating the data from one environment to another environment how would you manage the connections?
While migrating the folder or workflows make sure the connection name in both environment are same.
I. In the workspace or Navigator, select an object and click Versioning > View History.
II. Select the versions you want to compare and then click Compare > Selected Versions.
-Or-
Select a version and click Compare > Previous Version to compare a version of the object with the previous version.
The Diff Tool appears.
18. What is primary and backup node?
Primary node is a node where a current node or applications are running and backup node is defined to run the domain or applications services while primary node goes down
19. What is a grid in Informatica?
Grid in Informatica is used for load balancing. A grid is nothing but a combination of nodes which distributes the request among them.
Eg: node1, node2, node3, node4 are assigned in a grid. 10 workflows started simultaneously. Now instead of giving burden to a single node to run the 10 workflows the request for running workflows will be distributed to all nodes.
20. Can we create a Integration service without a Repository service and vice versa.
It is not possible to create an Integration service without a repository service however a repository can be created without an integration service.
21. Can we create multiple integration service on single repository?
Yes it is possible to create multiple integration service on single repository. This is used when you have to choose different code page for different integration service in same repository
Eg: Repository : ASIA_PACIFIC_Repo is used to load the data for countries specific to ASIA PACIFIC to target warehouse. Different Integration service created for non English countries to support different code page (Malaysia, China, Japan, Thailand)
22. What is native users.
Native users are the users created with admin console.
23. What is meant by LDAP users
LDAP users are the user which are configured with LDAP server (also may be MS Active directory ) and LDAP is integrated with power center to allow users to provide single sign on
24. What are roles and groups and benefits of using them?
25. What is domain and gateway node:
Domain is a single point of entry or the administrative unit in Informatica. All the request from different clients (like Designer) first reaches to domain and then routed to associated services. A gateway node is the node on which a domain is defined.
26. What is difference between a gateway node and worker node?
A gateway node is a node on which domain is defined and it act as a router or administrator to all services. All other nodes in a domain are worker nodes where application services like Informatica services, repository services will be running.
27. What do you understand by SOA of Informatica?
SOA or service oriented architecture allows the Informatica to have services on distributed system. You can define a domain on a node say node1 and repository service on node2, repository service on node3. All nodes can be anywhere within a network. Once a request is made from client it goes to the domain or the gateway node and then it directs the request to the appropriate nodes or services.
28. Is it possible to define a single node as a Gateway node as well as worker node?
Yes it is possible to define a node to act as both gateway node as well as worker node.
Eg: The domain is created on node1 and integration services and repository services are also running on the same machine or node. In this case a node will behave both as a domain and a worker node.
29. Can we create a node as a gateway node and the same node can be assigned to a grid?
Yes it is possible assign a gateway node to a grid.
30. Can we create two repositories on same database instance in oracle?
It is not possible to create two repositories on same instance of database in oracle as it will be creating the metadata tables for repository. However it is possible to create two repositories in oracle on same server if the database instance is different.
31. How do you take back up of repository?
Login to admin console. Select the repository-> Action->Backup Content
The backup content will be stored in a XML file and the location of backup directory is defined in domain configuration.
Also you can create a script and schedule it to backup the content on certain date and time.
In script first connect to repository using pmrep command and then backup the content with the below command.
Pmrep backup
-o
[-d ]
[-f (overwrite existing output file)]
[-b (skip workflow and session logs)]
[-j (skip deploy group history)]
[-q (skip MX data)]
[-v (skip task statistics)]
32. What is the difference between STOP and ABORT options in Workflow Monitor?
Stop waits for all running objects to complete and then terminate the process however abort stops the entire object running immediately.
Eg: A workflow is in running state and it’s having 5 sessions in it and only 2 sessions are running.
STOP: It will wait for the running sessions to complete their process and then terminate the workflow. Remaining 3 sessions will not run.
ABORT: It will kill the running session immediately and thus the workflow.
33. What happens when a session fails and you click on recover?
Every session has a property of commit interval. Commit interval is a point after which a session creates a log and commits the transaction at source, target or both levels. For each commit interval it generates an id corresponding for each row and when a session is recovered it reads the last id inserted to target and then proceeds the loading from next row.
Eg: Source is having 1000 rows and commit interval is set to 50 so it will commit for each 50 rows. Now session fails at row no 630. Now the target rows will be committed till 600th row as commit interval is 50. Once we recover a session the loading will start from 601th row.
34. What could be the possible resons of locks by user.
?Network problems occur.
?A PowerCenter Client, Integration Service, Repository Service, or database machine shuts down improperly.
35. What is exclusive and normal mode for repository services?
Exclusive mode is a mode defined while you make any changes to repository service. It’s like a lock while you play with repository configuration so its associated services like integration services will not be able to use its services.
36. What all are steps in up gradation of Informatica server?
To upgrade Informatica power center from one version to other version follow the below steps.
1. Upgrade Informatica server
2. Login to admin console help->About Informatica administrator and see the upgraded version
3. Select on repository Action->Content->Upgrade
4. Select on repository action-Content->upgrade users and groups
37. Is it possible to use a client with different version than that of its Informatica server?
It’s not possible use client with different version than that of its Informatica server.
38. How would you copy the content of one repository to another repository(The new repository is not having anything in it)
backup the repository using pmrep and the restore the content on new repository.
39. What do mean by local and global repository?
Local repository is a repository whose objects are accessible within that repository only.
Global repository: is a repository is a repository which can share its objects among the domain in different repository.
Eg: A mapping created in global repository can be accessed to all repositories in the domain.
40. Is it possible to revert a global repository to local one and why?
It is not possible to make global repository to local because its associated objects might be used by other repositories as well.
41. What is a shortcut and copy in Informatica and how two are different with each other.
A shortcut is a object which is defined inside a shared folder and used in different folders. Where as a copy is the replica of any object.
You cannot change the definition of a shortcut but can be changed in case of a copy.
Shortcut is useful in cases where source or target definition is same across multiple applications.
You just need to drag the source from shared folder and change the connections while creating a workflow in folder.
42. What do you mean by Parameter file? Why do we use it and what all things we can define in a parameter file?
Parameter file is a file assigned to a session which has configuration details in it. The parameter file is used for reusability. Below things are defined in it.
Connections, mapping parameter, mapping variable
43. How do you manage the Parameter files while migrating your data from one environment to another environment?
While migrating the data from one environment to other the parameter file should also be copied to new location else the file name on both environments can be same and then just we have to modify the parameter file to pint to the correct environment
44. What all challenges you faced in Informatica in your last project as an admin and how did you resolve them?
The oracle client was not installed properly on Informatica server and also the tns entry in oracle client was not properly. During Informatica server installation the domain was not able to ping to the database due to the client issue.
2. The Informatica admin console was not opening due to open files in OS
Used ulimit –n command to check open files and then increased the no to 4096.
45. If your server is running on Unix and one of the sessions are keep on running without loading any data how would you kill it.
type the below command in command prompt
Ps –ef |grep pm
Check the id for the running session and then kill it using kill command
Kill -9 id
46. What does “tail –f” command do and what is its use as an Informatica admin.
This command is used to follow the log file which keeps on appending.
47. How do you start and stop services in unix without using admin console
infaservice.sh startup shutdown
48. What is a difference between complete, stop and abort
?Complete: Allows the sessions and workflows to run to completion before disabling the service process.
?Stop: Stops all sessions and workflows and then disables the service process.
?Abort: Attempts to stop all sessions and workflows before aborting them and disabling the service process
49. What do you mean by DTM and Load manager and what is difference between load manager and load balancer?
? Load Balancer: The Integration Service uses the Load Balancer to dispatch tasks. The Load Balancer dispatches tasks to achieve optimal performance. It may dispatch tasks to a single node or across the nodes in a grid.
? Data Transformation Manager (DTM) process: The Integration Service starts a DTM process to run each Session and Command task within a workflow. The DTM process performs session validations, creates threads to initialize the session, read, write, and transform data, and handles pre- and post- session operations.
50. I am not able to connect to the domain with the client although all services and databases are up and there is no network issue.
Manage user connections and locks