Cognos Interview Questions and Answers - Freshers & Experienced

What is the enterprise class platform architecture of Cognos 8?

Cognos is used as a business intelligence platform made by IBM. It consists of all the capabilities that is being provided like view, create, manage, analysis, events. These functionalities are accessed from web interface. It provides a convenient way to manage the business that uses the business related applications to promote the centralized administration that is web-based. It is used to show a complete set of activities to solve the issues related to business practices. The platform of Cognos 8 is built on Service-Oriented-architecture (SOA) and it provides features like scalability, availability and maintainability.

It consists of three server tiers and they are named as:
- Web tier
- Application tier
- Data tier

What are the services provided in Cognos 8?

The services of reliability and scalability are provided in Cognos platform that allowed easy performance of it at the application tier level on the peer-peer basis. The services allowed the request to be satisfied with the complete response of the request that has come. This service provides fault tolerance technique that allows the platform to be more stable during the error that might cause the damage. Dispatching of the request is done using the automatic response and load balancing feature that is built in the system. The service allows the platform to be more optimized, which allow the access to the data sources and it includes the data sources related to each other. Online analytical processing (OLAP) is used for queries that need to be processed. The services can be accessed through the web tier.

What are the components used in Web Tier?

Web tier represents the controller that receives the incoming HTTP request invoking the logic that performs the operation in application model. The result of the operation allows the selection to be made using the controller to display the view.

The components that are present in the web tier are as follows:

- Gateway is used to request the Cognos for the services that is being provided to and from the dispatcher that allow the request to be redirected to the browser.

- CGI (common gateway interface), Servlets, Apache and others are used to provide a way to allow the transfer of data between two systems without any glitches.

- CGI should be avoided as it becomes very heavy to be used on the server until it is supported gateway in the web browser.

- Support for the TCP/IP protocols and sockets or the SSL (Secure socket layer) to secure the server related functionality and transfer of data can be done securly.

What are the roles defined by Cognos Platform?

Cognos platform uses of three tiers with different components and roles that is required to successfully implement it and provide good performance.

The roles that are defined by the web server:

- Ensuring of optimal performance by using, the services that are provided, by grouping the roles of the distributed deployment model used for the business intelligence application.

- Defining of one of the three tiers that are used within architecture alongside the business intelligence server that is used with it.

- It supports and provides the Gateway services. These services allow the communication to be performed between the user and the application that is given. A session is maintained for different components to fulfill the role of the Gateway.

- The component also allows the web-communication to be done using the resources that are minimal and provide high availability and scalability.

What are the components required for the application tier?

The application tier allows the logic tier to provide the presentation tier and the layer of its own. It also controls the application and its functionality by performing the details of processing.

The application tier is having the following components that are used:

- Multi-threading is used to share the work load and the processes that can consists of the distributable components.

- Multi-platform allows running one application on more than one platform with full functionality and no compatibility issues.

- It consists of the application server that can handle more than one application at a time and it is used to give the dynamic loading services that handle the request dynamically.

- Route the request of the content and the services that are associated with it, as it allows the request to be handled on time and the notification can be sent to solve the problem.

- IBM Cognos Dispatcher consists of the response that has to be dispatched from the server and it is used to allow quick responses by sharing the load.

What is the function of Cognos Dispatcher?

Cognos Dispatcher is used to provide the load balancing techniques and it is one of the methods used to handle the request of the application tier. The component of the Cognos dispatcher is a lightweight servlets that allow easy management of the application services and provide easy communication between many different applications. Cognos dispatcher stores the variable or the data during the startup. After the startup the local registers become available providing the services to the content manager. The server by this can be made configurable and the algorithm that will be used is round-robin to increase the performance of the system. The performance can be increased by defining the Cognos configuration file that consists of the reports of all the processes that are running on the system.

What is the information present in the Cognos configuration file?

The configuration file of Cognos is the normal configuration file that includes Cognos Dispatcher and IBM Cognos Report Server processes that is allocated to give it to the processor for faster processing of the resources. The configuration file consists of three to four low affinity threads and one high affinity thread. The threads are managed by using the traffic, which an application can handle. Affinity represents the report service that is provided to the original client from whom the request has come and there can be multiple interactions allowed to satisfy the request. High affinity connections are provided to process the requests from the service report.

What is the difference between low affinity and high affinity connections?

- Low affinity connections are used to show the requests that are presented by the report service depending on the priority level and the criticality of the request that is being made to use it, whereas high affinity connection processes the request, from, the report, services.

- Low affinity connection provides a way to show only the basic functionality and hide most of the complex methods and features from the client. Whereas, the high affinity connection shows the complete requests coming from the requests of the client.

- High affinity shows the request and it also gives the transaction that requires the performance. This is requested by the accessing the cache. Whereas, Low affinity can be made on any name and any service.

- Low affinity show the reports and notify the user about the reporting services and the process that is undertaken. Whereas, high affinity shows the threads that is required the console to set the connections according to the block title.

What are the main services provided by application tier?

Application tier provides the report or query service to be provided using the Cognos dispatcher that dispatches the code used to handle the dynamic request for the load that is getting on the server. The administrator in this case maximizes the number of processes and the services can start with the minimum number of processes. Configuration of the processes can be performed by using the report servers used to report to the processors that are available. The service performance gets increased using the processor speed and the functionality also increases due to the increment in the hardware capacity. To utilize the full capability of the server the Java heap size gets modified in the server environment and the query service can be made. The report services are launched using the interface libraries of Java.

What are the considerations regarding performance kept in mind while setting up cognos?

The performance considerations are very important in setting up the Cognos as the data source need to be transferred from one place to another so the query performance is bound to the server that is the host of the data source. The data source that is used by the server comes with the relational data sources that use the requirements that are for business community and that perform better than others. The database administrator can monitor the changes that are being done in the data source and it allows the requirements to be met by managing the overall database system. This optimizes the performance of the database as well as overall server’s performance. The server meets all the requirements that are defined in the three tier and it provides the components to scale, extend and make it available using the defined services.

What is the deployment requirements used in Cognos?

The deployment requirements have many options and many other recommendations that are requirement to successfully install and configure Cognos.

It includes the following steps:

- Use a single server and an instance of operating system that is associated with the multiple instances of the Cognos. This instance is also known as Platform instances, Report server and Content managers that is required to implement the application in the server profile and in the JVM instance.

- Configuration of the physical server or a virtualized platform that a client is using per instance of the application tier instances.

- User servers that are separate from the store, database and OLAP data source.

- No requirement to subscribe to the COU resources that are implemented throughout. The number of processors that are associated with the virtual guest instances that are running on the server.

What are the different types of important services used in Cognos?

The services that are used in Cognos:

- Agent service: This is the service that produces the output of the running agents. This service allows some service related conditions to be created and it store the generation of the event list. It is the service that allows keeping track of the agents that are running and working on the same module.

- Annotation service: This is the service that allows the reports to be generated. There should be quotes inside it and the local variables are produced by it.

- Batch report service: It allows the management of the request or allow it to run the reports. This functionality is provided using the background requesting to start the reports and the output is to be provided to the monitor service.

- Content manager service: This service is used for client interaction with the store content. The modification function will consists of add, query, delete, etc. This is also used an overall handler to handle the request and report.

- Content manager cache service: This allows the performance to be done and cache enhances the security. It caches the service that allows the overall system performance date.

Why are Meta service important then other services?

Metadata service allow to provide the support for the data information that is being displayed using the feature Cognos Viewer and other tools provided by Cognos. It is used to provide support for the lineage information that includes the data source and expression that require calculations. Metadata service gives an easy way to integrate the information system with applications. It supports the exchange of the model data using the development tools. It can be used for the sole purpose to integrate a component of the custom application that processes the management services to share the models. It also extends the functionality to support new tools to customize according to the requirement.

What is the importance of having monitor service in Cognos?

Monitor service allow easy handling of all the applications that are running and the requests that is being processed. It includes the scheduled tasks, reports that gets generated after the execution of the program and then the result gets emailed to the client who sent the request. Monitor receives the request that has to be executed to allow the request to be queued and available when one request is being responded to. Monitor service reduces the load on the server by noticing and forwarding the task to the service that is used to execute the application. Monitor service handles all the tasks and the exceptions that can occur during the application handling. Search indexing task that is included in this service allow the activities to be ordered and controlled from a centralized position.

What are the different kinds of panes included in Cognos?

The pane allow the content and the component to be organized together to give more convenient way for the user to use the functionalities given.

The panes are as follows:

- Project Viewer pane: It provides an easy way to access the project files which the user have defined. This store the files in a tree view and the project objects are displayed on the left side of the window.

- Project Info pane: It includes the project’s objects that is defined using different methods and provide the information of each file used in the project. It includes of three panes like Explorer, Diagram and Dimension map that allow easy creation, modifying, configuring and deleting of the objects. The search tab is used to define the properties of the project object for which the information can be gathered.

- Properties pane: It allows the configuration and modification of different properties of project’s object. This is given in the bottom middle of the window and display individual properties according to the object that is being used.

- Tools pane: It allows user to use tools that are available during the creation of the project. It is used to allow tools to switch the language or the project’s object, to view statistics and to perform the tasks that can be performed on a project. It provides easy to drag and drop of an object.

How is Cognos model organization works?

The Cognos model is managed in layers that consists of three root namespaces that allow unique identification to be given to each variable that is used and allow the libraries that are defined externally to be included.

Following are the three used namespaces:

- Data source objects: They allow the data source to be present and the sending and receiving of the request and response can be performed from one place. The data source object allows the fetching of the data and give it to the user.

- Model query subjects: They are used to produce the model and allow more than one model to be consolidated at one place and allow easy query subjects to be passed to the client.

- Metadata: It produces the data source query subjects and allow the user to define their data so that it can be easily found by the search engines.

- Namespace layers: They allow different views to be used to represent the different kinds of layers.

Explain the different types of views used in Cognos.

There are three different types of views that show the representation of the layers.

Different types of views used in Cognos are:

- Physical View: This view consists of the data source query subjects that are imported using different data sources. This data can be modified according to the need but it is not recommended to do it. It consists of all the metadata that require producing queries that are useful and efficient during the run time or dynamically. This also consists of the metadata to create the model query subjects.

- Business View: It consists of the model query subjects used to restructure the physical view to allow it to meet the requirements of the client or the information. The presentation of the metadata will not be shown to the user and it will help other sites to locate the data sources that are used by the user.

- Presentation View: It allows the grouping to be done using the star schema that shows the logical grouping of facts and the dimensions of the query subjects that are used for the data source used in presenting the content. The namespaces are concerned when one or more star schemas are selected and it provide unique name to those that exist in multiple names.

What is the function of Model Design Accelerator?

Model design accelerator consists of the layers used to implement the filters and the calculations that are related to business logic. It is a methodology that allows applying the logic to the different layers. It provides a layer that acts as insulation between the report and the logic that is defined to display the report. The reports that are generated using the model logic and then fed into model design accelerator. This allows keeping the data and managing it from a single place. If any data source changes then it becomes easier to remap the view of the data source using the physical view without changing anything in the report. The report query object will consists of items that allow the layer to be given as easy to use and friendly for all the people using it. It allows the design accelerator to increase the performance and less delay is produced.

What is the use of PowerPlay Web viewer in Cognos?

PowerPlay Web Viewer is a reporting tool that uses to view and analyze the reports of the web or made using the Cognos platform. It is reporting tool allowing the information to be made in the document format. It is used to provide the high quality format reports for the web. The information that is provided in the report can be customized and the publication of the report can be done by choosing the filters and dimensions provided with the tool. The customization can take place by taking the information in a report and by choosing the dimensions, row and column in which the content will be placed, suppression settings, headings to be put, and other formats that are used to customize it according to the requirement of the user. The selection is made for the changes that refresh the reports used to produce new information.

Why is Auto-regression used in forecasting used on Cognos platform?

The auto-regression method is used to show the auto-correlation method in forecasting. It provides easy detection to linear, non-linear, seasonal and data fluctuations using the projects to generate the report every time a new change comes. It provides the reliability factors that have business affecting the seasonal fluctuations. This provides the reliable forecast for the items that are being shown on the store. It is far better use than the Growth method, by using forecasting method large number of time periods can be taken to represent the seasonal variations. This is the model that provides a group of linear prediction that gives an output on the basis of the system that considers the previous outputs as well.
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