Top IBM DataStage Interview Questions and Answers

IBM InfoSphere Information Server's DataStage is a prominent ETL (Extract, Transform, Load) tool. For data integration from the data source system to the target system, DataStage is utilized by enterprises working with big data sets and warehouses. DataStage Developer, ETL Developer, DataStage Production Manager, and other DataStage job categories are popular.
   

1. Basic DataStage Interview Questions

1. The most basic DataStage interview question is to define DataStage.

DataStage is an ETL application for Windows servers that extracts, transforms, and loads data from databases into the data warehouse. It's used to create, test, and operate various applications that populate data warehouses and data marts. The IBM InfoSphere Data Integration Suite is incomplete without DataStage.

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2. What are DataStage characteristics?

DataStage uses a scalable parallel processing technology to facilitate the transformation of massive volumes of data. It helps Big Data Hadoop by allowing users to access data in a variety of ways, including via a distributed file system, JSON support, and a JDBC connector. With its improved speed, flexibility, and efficacy for data integration, DataStage is simple to use. DataStage can be used on-premises or in the cloud, depending on the situation.

3. How is a DataStage source file populated?

A source file can be populated in a variety of methods, such by using an Oracle SQL query or a row generator extract tool.

4. How is merging done in DataStage?

The main key column in the tables can be used to merge or combine two or more tables.

5. One of the most frequently asked DataStage interview questions is what is the difference between DataStage 7.0 and 7.5?

Many additional stages have been introduced to DataStage 7.5 over version 7.0, resulting in better stability and smoother performance. The command stage, process stage, report generation, and more are among the new features.
 

2. Intermediate DataStage Interview Questions-

1. What steps should be taken to improve DataStage jobs?

We must first create baselines. Also, performance testing should not be limited to a single flow. Work should be done in little increments. Evaluate data skews before isolating and resolving the issues one by one. Then, if there are any bottlenecks, distribute the file systems. RDBMS should not be used at the start of the testing process.
 

2. What is the quality state in DataStage?

With the DataStage tool, the quality metric is used for data purification. It's a client-server application that comes with IBM's information server.

3. One of the most frequently asked DataStage interview questions defines job control.

A tool for controlling a job or running numerous jobs in parallel is called job control. Job control is implemented using the IBM Datastage tool's Job Control Language.

4. How to do DataStage job performance tuning?

We begin by selecting the appropriate configuration files, partition, and buffer memory. Data sorting and null-time values are handled by us. Instead of using the transformer, we should try to utilize copy, modify, or filter. It is vital to limit the amount of superfluous metadata that is propagated between phases.

5. What is a repository table in DataStage?

For ad-hoc, historical, analytical, or complicated queries, a repository table or data warehouse is employed. It is possible to have a centralized or distributed repository.
 

3. Advanced DataStage Interview Questions-

1. What are the command line functions that can help to import and export DS jobs?

DS jobs are imported using dsimport.exe and exported using dsexport.exe.

2. Name the different types of lookups in DataStage.

There are four types of lookups: normal, sparse, range, and caseless.

3. How do you run a job using the command line?

This is how we use the command line to run a job:
dsjob -run -jobstatus dsjob -run -jobstatus dsjob -run -jobstatus dsjob -run -jobstatus ds

4. What is Usage Analysis?

To see if a job is part of the sequence, right-click on the job manager and choose Usage Analysis from the menu.

5. Another frequently asked DataStage interview question is what is the difference between sequential files and hash files?

A hash file can be used with a key-value because it is based on the hash algorithm. A sequential file, on the other hand, does not have a key-value column.
 
A hash file can be used as a lookup reference, whereas a sequential file cannot. The presence of a hash key makes it easier to search a hash file.
 
  IBM Datastage is a powerful tool for planning, building, and executing applications that extract data from databases and fill data warehouses.