Sqoop is one of the most commonly used data transfer tools that are primarily used to transfer the data between relational database management servers (RDBMS) and the Hadoop Ecosystem. It is an open-source tool that imports the different types of data from RDBMSs, such as Oracle, MySQL, etc., into the HDFS (Hadoop file system). It also helps in exporting the data from the HDFS to RDBMS.
With the growing demand for customisation and data-based research, the number of job opportunities for Sqoop professionals has seen a tremendous increase. If you are figuring out the best way to appear for a Sqoop interview and want to know some of the potential scoop interview questions that can be asked in 2022
, this article is the right place to get started.
We all know that every interview is designed differently according to the mindset of the interviewer and the requirements of the employer. Considering all this, we have designed a set of important Sqoop interview questions that can be potentially asked by an interviewer in a general case.
Sqoop Interview Questions & Answers
Q1. How does the JDBC driver help in the setup of Sqoop?
A: The major task of a JDBC driver is to integrate various relational databases with Sqoop. Nearly all database vendors develop the JDBC connector, which is available in the form of a driver that is specific to a particular database. So, in order to interact with a database, Sqoop uses the JDBC driver of that particular database.
Q2. How can we control the number of mappers using the Sqoop command?
A: The number of mappers can be easily controlled in Sqoop with the help of the parameter –num-mapers command in Sqoop. The number of map tasks is controlled by the –num-mappers arguments, which eventually can be seen as the degree of total parallelism being utilized. It is highly recommended that one should start with a small number of tasks and then keep on increasing the number of mappers.
Syntax: “-m, –num-mappers”
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Q3. What do you know about the Sqoop metastore?
A: The Sqoop metastore is one of the most commonly used tools in the Sqoop ecosystem, which helps the user to configure the Sqoop application in order to integrate the hosting process of a shared repository that is present in the form of metadata. This metastore is very helpful in executing jobs and managing different users based on their roles and tasks.
In order to achieve tasks efficiently, Sqoop allows multiple users to perform multiple tasks or activities simultaneously. By default, the Sqoop metastore will be defined as an in-memory representation. Whenever a task is generated within Sqoop, its definition is stored within the metastore and can also be listed if needed with the help of Sqoop jobs.
Q4. What are some contrasting features among Sqoop, flume, and distcp?
A: The major purpose of both Sqoop and Distcp is transferring the data. Diving in deeper, distcp is primarily utilized for sending any type of data from a Hadoop cluster to another. On the other hand, Sqoop is used to transfer the data between RDBMSs and the Hadoop ecosystems like HDFS, Hive, and HBase. Although the sources and destinations are different, both Sqoop and distcp use a similar approach to copy the data, that is, transfer/pull.
Flume is known to follow an agent-based architecture. It has a distributed tool for streaming different logs into the Hadoop ecosystem. On the other hand, Sqoop majorly relies on connector-based architecture.
Flume gathers and joins enormous amounts of log data. Flume is able to gather data from various resources. It doesn’t even take into account the schema or structuring of data. Flume has the ability to fetch any type of data. Since Sqoop is able to collect the RDMS data, the schema is compulsory for Sqoop to process. On an average case, for moving bulk workloads, flume is considered to be the ideal option.
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Q5: List out some common commands used in Sqoop.
A: Here is a list of some of the basic commands that are commonly used in Sqoop:
- Codegen – Codegen is needed to formulate code that will communicate with database records.
- Eval – Eval is used to run sample SQL queries for the databases and present the outcomes on the console.
- Help – Help gives a list of all the commands available.
- Import – Import is used to fetch the table into the Hadoop Ecosystem.
- Export – Export helps in exporting the HDFS Data to RDMBSs.
- Create-hive-table – The create-hive-table command helps in fetching the table definition into Hive.
- Import-all-tables – This command is used to fetch the tables from RDMSs to HDFS.
- List-databases – This command will present a list of all the databases live on a server.
- List-tables – This command will give a list of all the tables found in a database.
- Versions – The Versions command is used to display the current version information.
- Functions – Incremental Load, Parallel import/export, Comparison, Full load, Connectors for Kerberos Security Integration, RDBMS Databases, Load data directly into HDFS.
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These Sqoop interview questions should be of incredible assistance to you in your next job application process. While it is some of the time an inclination of the interviewer to contort some Sqoop questions, it ought not to be an issue for you in the event that you have your rudiments arranged.
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What is a JDBC driver, and what is it used for?
JDBC stands for Java Database Connectivity. It is used for creating Application Programming Interfaces (APIs) in Java. JDBC driver helps to connect the Java application to the database. It can be used to execute transactions. It also helps one to create objects that can connect to the database, execute queries, and return the results. Initially, a connection object is created which consists of the server name, username, and password. Then specific commands like Prepared, Callable, and Statements are used based on the type of query to be executed. The outputs of these queries are stored in arrays or objects.
What is Kerberos Security?
Kerberos is a network security protocol that uses cryptography to authenticate requests made from various computers over the Internet. It has been implemented while developing operating systems like Windows, Linux, and IOS. Kerberos has 3 main components, namely, the client, the server, and the Key Distribution Center (KDC). Kerberos provides authentication and can be an alternative for SSH, POP, and SMTP. The Ticket Granting Server (TGS) secret key, Server secret key, and a hash value generated from the users' password are the 3 secret keys used.
What is meant by Distcp?
Distcp stands for Distributed Copy. It is a command in Hadoop that distributes the copy operation among multiple nodes inside and outside the cluster. Copying of data leads to redundancy but ensures reliability. Even if data in a cluster is destroyed or corrupted, we can still retrieve it because we have multiple copies stored. It works well with MapReduce and ensures effective data distribution, error handling, and recovery. It updates files between various clusters, resizes maps such that every map has the same number of bytes, overwrites files in clusters, and also migrates data from Hadoop Distributed File System to a traditional file system.