Information Engineer Interview Questions – Nice Studying

data engineer interview questions

Do you may have a Information Engineer Interview arising? Congratulations! It is a extremely sought-after place within the tech trade, and with good motive. A knowledge engineer is answerable for managing and designing large information options, so the function requires intensive data of assorted large information applied sciences. If you wish to ace your interview and land the job, it is advisable be ready for questions on large information applied sciences, information engineering ideas, and extra. On this put up, we’ll stroll you thru among the most typical information engineer interview questions requested in interviews, and we’ll provide you with tips about find out how to reply them. 

Prime Information Engineer Interview Questions

Let’s get began with the highest information engineer interview questions.

Clarify Information Engineering.

Information engineering is the method of remodeling uncooked information right into a format that can be utilized for evaluation or downstream processing. This usually consists of information cleansing, transformation, and modelling. 

What are the varied kinds of design schemas in Information Modelling? 

Information engineers use quite a lot of design schemas in information modelling, together with entity-relationship diagrams, truth tables, and star schemas. 

Distinguish between structured and unstructured information. 

Structured information is information that’s organized in a selected format, whereas unstructured information is any information that’s not organized in a selected format. 

What’s NameNode? 

The NameNode is a key element of the Hadoop Distributed File System (HDFS) and manages the metadata for the entire recordsdata within the system. 

What’s Hadoop? 

Hadoop is a software program framework that enables for the distributed processing of huge information units throughout clusters of servers. It’s designed to scale up from single servers to 1000’s of nodes, every providing native computation and storage. 

Outline Hadoop streaming. 

Hadoop streaming is a course of that means that you can run MapReduce jobs immediately in your pc, with out the necessity for a Hadoop cluster. This may be helpful for growth, testing, or while you don’t have entry to a Hadoop cluster. 

What’s the full type of HDFS? 

The total type of HDFS is Hadoop Distributed File System, which supplies scalable information storage. 

Clarify all elements of a Hadoop software. 

There are 4 most important elements of a Hadoop software: the MapReduce engine, HDFS, YARN, and the Zookeeper ensemble. 

The MapReduce engine is answerable for dividing the enter information into particular person map duties and working them on the employee nodes. HDFS is answerable for storing the enter information and output recordsdata from the Hadoop MapReduce job. YARN manages assets on the cluster, together with reminiscence and CPU utilization. Zookeeper helps keep communication between the entire elements in a Hadoop software. 

Clarify Star Schema. 

In a star schema, all of the tables are related to a central desk (often referred to as the very fact desk). This central desk shops all the information and is related to all the opposite tables. 

What’s Snowflake? 

Snowflake is an information warehouse that was designed for the cloud. It separates information into particular person tables and shards them throughout a number of servers. This helps remove the necessity for predefined schemas and permits customers to run SQL queries on the information. 

Clarify intimately what occurs when Block Scanner detects a corrupted information block?

When Block Scanner detects a corrupted information block, it takes the next steps:

  1. The block is recognized and despatched to a remediation server. 
  2. The block is verified and repaired if potential. 
  3. The block is restored to its unique location. 
  4. The block is re-indexed. 
  5. The corrupted pages are marked as such within the index file. 
  6. The index file is compressed and despatched to the consumer. 

What’s Massive Information? 

Massive information is a time period used to explain the massive quantity of knowledge – each structured and unstructured – that organizations face right this moment. 

Title two messages that NameNode will get from DataNode? 

NameNode will get two messages from DataNode. One message is in regards to the addition of recent blocks to the DFS, and the opposite message is in regards to the elimination of blocks from the DFS. 

Record out varied XML configuration recordsdata in Hadoop? 

There are numerous XML configuration recordsdata in Hadoop. The recordsdata are core-site.xml, hdfs-site.xml, mapred-site.xml, and yarn-site.xml. 

What are the 4 V’s of massive information? 

Quantity, Velocity, Selection, and Veracity are the 4 V’s of massive information. 

Clarify the options of Hadoop. 

The excellent options of Hadoop are that it’s scalable, dependable, and fault-tolerant. It helps a big cluster of nodes and likewise parallel processing. 

Distinguish between Star and Snowflake Schema. 

In a star schema, all of the tables are related to a central desk (often referred to as the very fact desk). This central desk shops all the information and is related to all the opposite tables. A snowflake schema is just like a star schema, however as a substitute of a central desk, there’s a central truth desk that’s related to a number of dimension tables. 

Clarify Hadoop distributed file system. 

HDFS abbreviates Hadoop distributed file system. It’s a distributed file system that shops information throughout a number of servers. This enables for prime availability and fault tolerance. HDFS additionally helps parallel processing, which permits information to be processed in parallel on a number of nodes. 

Clarify Secure mode in HDFS. 

Secure mode is a function that allows HDFS to get well from failures. When HDFS enters protected mode, it stops all writing operations and begins studying from the final checkpoint. This ensures that no information is misplaced if there’s a failure. 

Record varied modes in Hadoop. 

The next are the varied modes in Hadoop: 

  1. Standalone mode 
  2. Pseudo-distributed mode 
  3. Totally distributed mode. 

What’s the full type of YARN? 

YARN stands for But One other Useful resource Negotiator. It’s a cluster useful resource administration framework that was launched in Hadoop 2.0. It manages assets for each MapReduce and Spark purposes. 

The way to obtain safety in Hadoop? 

There are three safety modes in Hadoop: safety, authentication, and authorization. Safety mode ensures that every one information is encrypted whereas it’s at relaxation. Authentication mode verifies person identities earlier than permitting entry to assets. Authorization mode determines which operations customers are allowed to carry out on assets. 

What’s Heartbeat in Hadoop? 

Heartbeat helps handle Heartbeat failures in HDFS clusters. If a node fails, the Heartbeat daemon on different nodes will detect the failure and mark the node as down. The JobTracker will then begin new duties on different nodes. 

What’s FIFO scheduling? 

FIFO stands for First-In-First-Out. FIFO scheduling ensures that duties are scheduled within the order during which they have been submitted in order that duties with shorter execution occasions will not be starved for assets. 

Distinguish between NAS and DAS in Hadoop. 

The phrases Community-Connected Storage (NAS) and Direct-Connected Storage (DAS) are sometimes used when discussing Hadoop. Nonetheless, they could be a little complicated, so let’s break them down. 

NAS is a storage gadget that’s related to a community, whereas DAS is a storage gadget that’s related on to a server. In Hadoop, the NameNode and JobTracker run on the NAS, whereas the TaskTracker runs on the DAS. 

Record a number of key fields or languages utilized by information engineers. 

The primary fields utilized by information engineers are Python, Java, and Scala. Nonetheless, many different languages are additionally used. 

What are the default port numbers on which NameNode, activity tracker, and job tracker run in Hadoop? 

The default port numbers for the NameNode, JobTracker, and TaskTracker are 8020, 8030, and 8081 respectively. 

What’s the largest problem you confronted as a Information Engineer? 

The largest problem that information engineers face is managing and processing giant quantities of knowledge. Information can are available in many alternative types and may be saved in many alternative methods. As an information engineer, you want to have the ability to perceive the information and know-how to course of it in a manner that meets the wants of the enterprise. 

One other widespread problem is guaranteeing information integrity. As an information engineer, it is advisable be sure that the information is saved appropriately and is accessible when wanted. You additionally must be sure that the information is safe and that solely licensed personnel can entry it. 

Along with these challenges, information engineers additionally should be conversant in HDFS and its options. They should know find out how to function HDFS in a protected mode and perceive how rack consciousness impacts the distribution of knowledge. 

What are among the most typical applied sciences utilized in Information Engineering? 

By way of applied sciences, information engineering is commonly constructed on prime of Hadoop and MapReduce. Different applied sciences that could be used embody Hive, Pig, Spark, and NoSQL databases. 

Clarify what would occur when NameNode is down, and the person submits a brand new job? 

By way of what occurs when NameNode is down, the person submits a brand new job. The person can’t submit a brand new job for execution since NameNodeis a single level of failure. It leads to job failure, therefore wanting the person to restart the NameNode earlier than working any job. 

Why does Hadoop use Context objects? 

The Context object is utilized by the Hadoop Distributed File System (HDFS) to retailer and handle recordsdata. The Context object shops details about the file, together with the identify of the file and the placement of the information. The Context object additionally shops details about the nodes within the cluster, together with the identify of the node, the kind of node, and the handle of the node. This info is utilized by HDFS to find and entry recordsdata on completely different nodes within the cluster. 

Clarify the significance of Distributed Cache in Apache Hadoop?

Distributed Cache: It’s used to retailer and distribute recordsdata between nodes in a cluster.

What do you imply by SerDe in Hive? 

SerDe: It’s used to course of and browse information from Hive tables. 

Record elements accessible within the Hive information mannequin. 

Parts in Hive Information Mannequin: These embody tables, partitions, recordsdata, and columns. 

What’s the usage of Hive within the Hadoop ecosystem? 

Hive in Hadoop Ecosystem: Hive supplies a option to course of information saved in HDFS and makes it straightforward to question that information utilizing the SQL-like HiveQL language. 

Inform me a couple of time while you needed to work with tough information. 

When answering this query, it’s necessary to keep in mind that information engineering is all about fixing tough issues. So, you wish to select an instance that showcases your expertise and talents as an information engineer. 

Record varied advanced information varieties/collections supported by Hive. Clarify how the .hiverc file in Hive is used for?

Some widespread advanced information varieties/collections which are supported by Hive embody textual content recordsdata, Parquet recordsdata, ORC recordsdata, and Avro recordsdata. As well as, you may as well use .hiverc recordsdata in Hive to specify extra configuration choices on your Hive tables. 

What’s a Skewed desk in Hive? 

A skewed desk is a desk that doesn’t have a uniform distribution of knowledge values. This may be problematic for a lot of causes, similar to while you’re attempting to run a question in opposition to the desk. In Hive, you need to use the Skewed desk operate to determine and repair skewed tables. 

Is there a risk to create multiple desk in Hive for a single information file? 

You possibly can create multiple desk in Hive for a single information file. If you create a desk in Hive, you’re specifying the SerDe for use to deserialize the information. 

Clarify completely different SerDe implementations accessible in Hive. 

There are a number of completely different SerDe implementations accessible in Hive, every with its advantages and downsides. The default serde, org. apache.Hadoop.hive.serde2.lazy SimpleSerDe may be very quick however doesn’t assist all information varieties. For those who want extra options, you need to use a unique SerDe like org.apache.hadoop.hive.serde2.json JSONSerde or org.apache.hadoop.hive.serde2.xml XMLSerde. 

Record desk producing features accessible in Hive. 

There are additionally a number of table-generating features accessible in Hive that may make your life loads simpler when working with information recordsdata. These features embody GENERATE_TBL_IF, GENERATE_ORC_TBL, and GENERATE_AVRO_TBL, which can all generate tables primarily based on the enter information file you specify. 

Level out the objects created by creating an announcement in MySQL. 

If you run the MySQL command, it opens up a MySQL immediate. At this immediate, you possibly can kind in SQL statements to control your MySQL databases and tables. 

The commonest SQL assertion utilized in MySQL is the create assertion, which is used to create new databases and tables. If you run the create assertion, MySQL will create a brand new database or desk, and also will robotically create the entire crucial database objects and columns wanted to retailer information. 

The next are a number of of the objects created: 

  • Database 
  • Index 
  • Desk 
  • Person 
  • Process 
  • Set off 
  • Occasion 
  • View 
  • Perform 

The way to see the database construction in MySQL? 

To see the construction of a MySQL desk, you need to use the desc command. This can present you the entire columns which are contained within the desk, in addition to their information varieties and sizes. 

The way to seek for a selected String within the MySQL desk column? 

To seek for a selected String in a MySQL desk column, you need to use the next question: SELECT * FROM WHERE xxx LIKE ‘%%’. This can return the entire rows from the desk that incorporates the string that you just specify. 

Clarify how information analytics and large information can contribute to rising the corporate income? 

Rising firm income is among the main targets for any enterprise. By utilizing information analytics and large information, an information engineer may help an organization determine alternatives to extend income and enhance the underside line. 

Clarify about design schemas accessible in information modelling? 

Information modelling is the method of making a construction for information in order that it may be simply understood and analyzed. There are a number of design schemas accessible in information modelling, every with its strengths and weaknesses. The commonest are entity-relationship diagramming, star schema, and snowflake schema. 

Clarify the distinction between an information engineer and an information scientist? 

A knowledge engineer is answerable for creating and sustaining the infrastructure wanted to retailer and entry information. This consists of designing and constructing databases, creating algorithms to extract insights from information, and creating fashions to assist predict future developments. A knowledge engineer can be answerable for guaranteeing that information is correctly cleansed and formatted earlier than it’s analyzed. 

A knowledge scientist is answerable for analyzing information to seek out patterns and insights. They use this info to develop hypotheses about how companies can enhance their efficiency. Information scientists usually use machine studying algorithms to automate the invention course of. 

What information is saved in NameNode? 

NameNode shops the metadata for the entire recordsdata within the Hadoop cluster. This consists of the trail to the file, its permissions, and the proprietor of the file. 

What do you imply by Rack Consciousness? 

Rack Consciousness is a function in Hadoop that detects when a node goes down and relocates the information to a different node. 

What are some widespread points you may have seen with Hadoop?

Widespread points with Hadoop embody information skew and HDFS blocks being too giant. 

How would you question an information set in Hadoop? 

Querying information in Hadoop may be executed with both Hive or Impala. 

What’s the default replication issue accessible in HDFS and What does it point out? 

In HDFS, the default replication issue is 3. Which means each block of knowledge is replicated 3 times. The replication issue may be modified on a per-file foundation or set to a decrease quantity if desired. 

What do you imply by Information Locality in Hadoop? 

Information locality in Hadoop refers to the concept that information must be saved as near the processing nodes as potential to attenuate community visitors and enhance efficiency. HDFS achieves information locality by replicating information blocks to nodes the place the related blocks are at the moment being processed. 

Outline Balancer in HDFS. 

The balancer in HDFS is a instrument that helps evenly distribute information blocks throughout the entire DataNodes in a cluster. This prevents anyone node from turning into overloaded whereas additionally guaranteeing that every one nodes have an equal quantity of knowledge. 

What can we do to disable Block Scanner on HDFS Information Node?

To disable the block scanner on an HDFS information node, you possibly can execute the next command: hdfs dfs –setBlockScannerEnabled false or dfs.datanode.scan.interval.hours to zero.

Outline the space between two nodes in Hadoop? 

The space between two nodes in Hadoop is outlined by the price of the community. By default, the price is 1. You possibly can change the price by utilizing the next command: 

Hadoop –set dfs.distance.metrics.widespread.command line “” 

The tactic getDistance() can be used to acquire the space between the 2 nodes.

Why use commodity {hardware} in Hadoop? 

Commodity {hardware} is utilized in Hadoop as a result of it’s inexpensive and simply scalable. Moreover, commodity {hardware} usually has an extended lifespan than conventional enterprise {hardware}. 

Outline replication consider HDFS. 

The replication issue specifies what number of copies of knowledge are saved on completely different nodes within the cluster. The default replication issue is 3. 

What Is the Distinction Between Hadoop and Snowflake? 

Hadoop and Snowflake are each information warehouses, however they work in numerous methods. Hadoop is an open-source platform that helps you retailer and course of giant quantities of knowledge. Snowflake, however, is a proprietary platform that helps you retailer, course of, and analyze information rapidly and simply. 


Getting ready for an information engineer interview can appear daunting, however by understanding what to anticipate and training your solutions, you possibly can really feel assured and ready. These are among the most typical information engineer interview questions that you’ll doubtless be requested in an information engineer interview, so be sure to are conversant in them and have a stable reply prepared.

The info engineering discipline is rising quickly, and corporations are on the lookout for expert information engineers to hitch their groups. For those who’re seeking to make a transfer into information engineering, otherwise you’re simply getting began within the discipline, you’ll doubtless must interview for a place. Congratulations on making it to the interview stage! Now it’s time to nail the information engineer interview questions and land the job. As an information engineer, you possibly can count on to be requested about your expertise with large information techniques, dealing with and manipulating information, and your data of Hadoop. Be ready to reply questions on your previous tasks and the way you tackled tough issues. Keep calm and assured, and make sure you ask your questions on the finish of the interview. Good luck! Thanks for studying! We hope this text helps you in your job search.

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