Top 10 Snowflake Interview Questions (With Example Answers)

Updated 30 September 2022

Snowflake is a leading cloud-based data warehouse that operates across multiple-cloud infrastructure environments. If you are planning to attend a job interview for a data manager, data architect or other similar positions, employers might test your knowledge of the Snowflake platform during the interview. Learning how to answer interview questions on Snowflake can help you build a successful career in data warehousing. In this article, we list some common Snowflake interview questions and share their sample answers and tips to assist your interview preparation.

Snowflake Interview Questions With Sample Answers

Here is a list of Snowflake interview questions that you can expect in an upcoming interview:

1. What is Snowflake?

While this question might seem too obvious, interviewers often begin the session by asking simple questions. It helps the interviewer evaluate if you are familiar with the Snowflake platform and also serves as a warm-up before moving on to the more complex questions. To answer this question, you can explain all that you know about Snowflake and also highlight your experience working on it.

Example: 'Snowflake is a Software-as-a-Service (SaaS) data-warehouse platform built on top of popular cloud infrastructures. It provides businesses with flexible, powerful and scalable data storage solutions along with several business intelligence tools. It is a centralised platform for various data management tasks like data engineering, data lakes, data app development and advanced data analysis. Snowflake makes data warehousing affordable and convenient by offering numerous functionalities and easy-to-use features.'

2. What are the main layers of Snowflake's architecture?

Snowflake's architecture is a combination of shared-disk and shared-nothing database architectures. It utilises a central data repository that is available to all nodes, like in a shared-disk model. Additionally, it also has several massively parallel computing (MPP) clusters for handling queries like in a shared-nothing architecture. The interviewer might include this question to evaluate if you understand the theory behind Snowflake's architecture.

Example: 'Snowflake has three major architectural layers such as database storage layer, query processing layer and cloud services layer. The database storage layer reorganises data into a specific format and optimised format. The query processing layer executes queries using virtual warehouses and the cloud services layer provides administrative services like authentication, access control, infrastructure management, metadata management, query parsing and query optimisation.'

3. What do you mean by a virtual warehouse?

Virtual warehouses are a core feature of Snowflake. When answering conceptual questions like these, you can elaborate your answers by including benefits or examples, as applicable. This helps provide a cohesive structure to your response and impress the interviewer by differentiating your responses from other candidates.

Example: 'A virtual warehouse is a collection of several computing resources like central processing unit, solid-state drive and memory. Virtual warehouses do not share computing resources. Customers can access a virtual warehouse to load data, run queries and perform other data manipulation language (DML) and structured query language (SQL) operations. The biggest benefit of a virtual warehouse is cost-efficiency. You can pay for the warehouse based on data storage size, how long you run it and what services you use. As their performance is not dependent on each other, they offer better efficiency.'

4. I accidentally deleted a table. Is it possible to recover it in Snowflake?

The interviewer might ask hypothetical, situation-based questions to test your real-time problem-solving and logical reasoning skills. You can structure your answer to these questions by explaining Snowflake's relevant feature or functionality that helps you solve the issue. For this question, you can explain the 'time travel' feature in Snowflake that allows you to access historical data in the warehouse.

Example: 'We can recover the accidentally deleted data using the "time travel" feature. This feature makes it possible to travel back in time within a defined period to retrieve the lost data. Besides retrieving lost data, the time travel feature performs other tasks like analysing data usage and manipulations for a specific period, backup and duplicate data at or before specific points in the past.'

5. Can you use the time-travel feature to recover all old lost data?

The interviewer might ask follow-up questions based on your previous answer(s). So, during the interview, be prepared for more in-depth questions on the same topic. Explain the data retention period of Snowflake and how it helps retrieve lost data.

Example: 'Snowflake has a critical feature known as the data retention period that facilitates the application of the time-travel feature. For example, when you perform a data modification action like deletion, Snowflake preserves the previous data state for a specific period. By default, the data retention period is 24 hours for standard accounts and 0 to 90 days for enterprise accounts.'

6. Does that mean it is impossible to recover accidentally-lost data after the data retention period?

Some interviewers do not follow a pre-defined interview script but ask follow-up questions based on your answers. This is an excellent opportunity to impress the interviewer by demonstrating your in-depth knowledge of Snowflake's functionalities. To answer this question, you can explain how to use the fail-safe feature after the data retention period.

Example: 'Yes, it is possible to retrieve accidentally-lost data even after the data retention period. At the end of the data retention period, the fail-safe default period begins. Fail-safe allows us to retrieve long-lost data due to rare operational failures. It is a long process and can take hours or even days to complete the data recovery process.'

7. Why do you prefer Snowflake over other cloud-based data warehouse platforms?

With cloud-based data warehouses growing in popularity, there are several platforms available on the market. The interviewer might ask this question to evaluate if you know the advantages of using Snowflake for data warehousing operations. You can structure your answer by explaining Snowflake's key features and salient benefits compared to other popular data warehousing platforms.

Example: 'When compared with other popular data-warehousing platforms Snowflake offers several additional benefits. The biggest advantage of using Snowflake is that it requires zero maintenance as it is a complete SaaS solution. It uses always-on encryption to provide strict security checks, ensuring high levels of data security. Other benefits of Snowflake include scalability, reliable performance, cost-efficiency and business intelligence.'

8. How to access the Snowflake cloud data warehouse?

The interviewer might ask a few questions like these to test your practical knowledge of Snowflake. You can answer this question by explaining the different ways to access Snowflake's data warehouse.

Example: 'Snowflake provides several easy ways to access the warehouse. Some popular methods include using ODBC or JDBC drivers or Python libraries that connect to Snowflake using Python applications. We can also access the warehouse by using the SnowSQL command-line client or the corresponding web user interface.'

9. What are the differences between transient and temporary tables?

While answering questions comparing the differences between two concepts, you can demonstrate your understanding of the nuances of the underlying concept by explaining how it differs from each other. Begin the answer by explaining the definitions of both and explain how it differs from each other.

Example: 'Transient tables in Snowflake are similar to permanent tables, with the difference that they do not have a fail-safe period. Temporary tables exist only for a particular session. Transient tables help in storing transient data that you require for multiple sessions but do not require extra levels of data protection. Both transient and temporary tables contribute to the overall storage limits of Snowflake for each user account.'

10. Can you suggest a way to reduce Snowflake bills?

The interviewer might ask questions like this to test your business aptitude. You can answer this question by explaining data compression in Snowflake and how it lowers data warehousing charges.

Example: 'One of the biggest advantages of using Snowflake is that it charges customers based on their data size after compression and not the original data size. By compressing data, we can reduce storage costs. Also, other features like data cloning or sharing do not incur additional costs.'

Tips To Prepare For A Snowflake Interview

Here are a few tips that can help you improve your confidence for attending Snowflake interviews:

Understand the role you are applying for by reading the job description carefully. Identify the critical skills the employer is looking for and highlight these skills in your answers.
Review the company's past interview questions. Search for the company name along with the keyword 'Snowflake interview' to see if you can find any sample questions online and try solving them.
Use the Challenge-Action-Result (CAR) interview response method. This technique helps in presenting your answers clearly and effectively by demonstrating your problem-solving skills to the interviewer.
It is okay not to know the answers to a specific question. If you face any challenging question, you can let the interviewer know that you do not know the answer but are eager to learn more about it.

Please note that none of the companies, institutions or organisations mentioned in this article are affiliated with Indeed.