Top 10 PostgreSQL developer interview questions and answers

If you are looking to assemble a team of exceptional PostgreSQL developers for your team or looking to start off an excellent career as a PostgreSQL developer, you have come to the right place. Here, we will provide you with a carefully crafted list of 10 important PostgreSQL interview questions for advanced PostgreSQL developers, which will help you find your perfect fit, whether you are a recruiter or a developer.

Last updated on Mar 21, 2023

PostgreSQL is a popular Object-Relational Database Management system that is mostly used for web applications. Acing a PostgreSQL job interview as a developer is not the easiest thing to do. However, with our perfectly crafted PostgreSQL interview questions, which cover the majority of the important concepts and as well as practical applications, your PostgreSQL interview might just be a walk in the park. As a recruiter, we can help you secure the perfect advanced PostgreSQL developer for your company with our PostgreSQL interview questions.

PostgreSQL developer interview questions and answers


What is PostgreSQL and list down its main features?

In the SQL world, Postgres, often known as PostgreSQL, is a widely used Object-Relational Database Management System that is mostly utilized in various web applications. It is one of the most powerful open-source object-relational database systems. It extends and makes use of the SQL language, combining it with a variety of capabilities to reliably scale and store complex data workloads. It adds extra and significant power by embracing four key principles in such a way that the user may easily extend the system.

Some of the important features of PostgreSQL are:

  • PostgreSQL is an object-relational database
  • It supports major operating systems
  • Postgres also supports extensibility for SQL and JSON querying
  • Postgres supports multi-version concurrency control and procedural languages
  • Nested transactions are also supported in Postgres


What are functions in PostgreSQL?

Functions are crucial because they aid in the execution of code on the server. PL/pgSQL, PostgreSQL's native language, and other scripting languages such as Perl, Python, PHP, and others are some of the languages used to create functions. The statistical language PL/R can also be used to improve the functions' performance.


What is the maximum table size in PostgreSQL?

Although PostgreSQL allows users to create infinite databases, it does have a maximum table size limit. The maximum table size in PostgreSQL is 32 TB.


What does command enable-debug mean in PostgreSQL?

The command enable-debug is used to make all of the apps and libraries compile. This technique normally slows down the machine, but it also increases the size of the binary file. The presence of debugging symbols aids developers in discovering flaws and other issues that may emerge when working with their scripts.


Explain Multi-Version Concurrency Control in PostgreSQL.

In PostgreSQL, multi-version concurrency control, or MVCC, is used to minimize excessive database locking. The user no longer has to wait to log into his database. This feature or time lag happens when someone else is accessing the content. A record of all transactions is preserved.


What are the different data types in PostgreSQL?

PostgreSQL supports a myriad of data types:

  • Boolean
  • Numeric Types
  • Character Types
  • Temporal Types
  • Array
  • UUID
  • JSON
  • Store
  • Geometric data and other special types


Explain tokens in PostgreSQL.

Tokens are the fundamental components of any source code. Many of the special character symbols are known to be found in them. Constants, quoted identifiers, other identifiers, and keywords are examples of these. Tokens, or keywords, are pre-defined SQL instructions with pre-defined meanings. Variable names, such as columns and tables, are represented by identifiers.


What do CTIDs mean in PostgreSQL?

CTIDs is a column that exists in every PostgreSQL database and is used to identify individual physical rows inside a table based on their block and offset positions. Index entries utilize them to point to actual rows. It is distinct for each entry in the table and clearly identifies the tuple's position. Because the CTID of a logical row changes when it is changed, it cannot be utilized as a long-term row identifier. When no competing update is expected, it is occasionally advantageous to identify a row within a transaction.


How can you change a user's password in PostgreSQL?

In order to change a user’s password in PostgreSQL, follow these steps:

  • Through the root user, sudo, or via SSH public key verification, make yourself the ‘Postgres’ system user
  • Using ‘PSQL”, connect to the local server
  • Follow up by typing this particular meta-command of PSQL \password


What do you understand by pgadmin?

Pgadmin is a free, open-source database management GUI for PostgreSQL that runs on Microsoft Windows, Mac OS X, and Linux. Pgadmin is used to retrieve information from database servers and the development process, quality testing, and other continuous maintenance.

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Wrapping up

In conclusion, the above provided PostgreSQL interview questions provide you with the optimum amount of information and knowledge about PostgreSQL and its technical side. With these PostgreSQL questions, you should be able to easily ace your technical PostgreSQL interview or find the best PostgreSQL developers who are technically qualified. However, in order to ace your PostgreSQL interview, you need to start paying attention to soft skills. As a developer, you need to brush up on your soft skills as a recruiter is looking for a technically sound PostgreSQL developer and someone who gels perfectly with their team. A recruiter needs to pay attention to soft-skill questions, as they should hire the right candidate who would perfectly fit in their work environment. Therefore soft skills are as important as technical skills.

If you are ready with both your soft skills and technical prowess, why not head to and apply as a PostgreSQL developer. Join hands with Turing to hire from the top 1% of developers around the globe and assemble your dream team.

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