Top 50 Snowflake Interview Questions and Answers

What is Snowflake?
Snowflake is a cloud-based data warehousing platform designed for scalability, performance, and simplicity.
What are the key features of Snowflake?
- Cloud-native architecture
- Automatic scaling
- Separation of compute and storage
- Support for structured and semi-structured data
What is Snowflake’s architecture?
Snowflake uses a three-layer architecture:
- Database Storage: Stores data in optimized formats.
- Query Processing: Performs SQL execution.
- Cloud Services: Manages metadata, transactions, and security.
What makes Snowflake unique compared to traditional databases?
- Separation of compute and storage
- Elastic scalability
- Native support for semi-structured data (e.g., JSON, Parquet)
What cloud providers does Snowflake support?
Snowflake is available on AWS, Azure, and Google Cloud Platform.

How does Snowflake store data?
Snowflake stores data in an optimized columnar format in cloud storage.
What is micro-partitioning in Snowflake?
A data organization technique where data is automatically split into small partitions for performance optimization.
What is a Snowflake stage?
A staging area for loading and unloading data into or out of Snowflake.
What is the difference between external and internal stages?
- Internal Stages: Managed by Snowflake.
- External Stages: Points to external storage like AWS S3 or Azure Blob.
How does Snowflake handle data compression?
Snowflake automatically compresses data during storage using advanced algorithms.

What is virtual warehouse in Snowflake?
A compute resource for executing queries and performing data transformations.
What is the purpose of caching in Snowflake?
- Result Cache: Stores query results.
- Metadata Cache: Stores table metadata.
- Data Cache: Stores data in SSDs for faster access.
How does Snowflake handle concurrency?
Using multiple virtual warehouses to isolate workloads and avoid resource contention.
What is a Snowflake cluster key?
A key that optimizes query performance by clustering data within a table.
What is pruning in Snowflake?
A performance optimization technique where only relevant micro-partitions are scanned.

How do you create a database in Snowflake?
sql
CREATE DATABASE database_name;
What is a schema in Snowflake?
A logical grouping of database objects such as tables, views, and functions.
How do you perform data ingestion in Snowflake?
Using COPY INTO command to load data from stages into Snowflake tables.
How do you create a table in Snowflake?
sql
CREATE TABLE table_name (column1 datatype, column2 datatype);
What is Time Travel in Snowflake?
A feature that allows accessing historical data for a defined retention period.

How does Snowflake handle scaling?
- Horizontal Scaling: Increase virtual warehouses for concurrency.
- Vertical Scaling: Increase size of warehouses for processing power.
What is auto-suspend in Snowflake?
A feature to suspend inactive warehouses automatically to save costs.
What is auto-resume in Snowflake?
A feature to restart suspended warehouses automatically when needed.
How do you optimize queries in Snowflake?
- Use cluster keys.
- Minimize data scans.
- Leverage caching.
What is materialized view in Snowflake?
A view that stores query results for faster performance.

What are roles in Snowflake?
Roles control access to Snowflake objects and define user privileges.
What is multi-factor authentication (MFA) in Snowflake?
A security feature requiring an additional verification method during login.
What is a Snowflake account?
An isolated instance of Snowflake containing databases, schemas, and other resources.
What is Snowflake’s data encryption mechanism?
Snowflake encrypts data at rest and in transit using AES-256 encryption.
How do you manage user authentication in Snowflake?
Using methods like username/password, OAuth, SAML, and federated authentication.

How does Snowflake support semi-structured data?
By using the VARIANT data type to store JSON, Avro, ORC, or Parquet files.
What is the FLATTEN function in Snowflake?
A function to transform semi-structured data into a relational format.
How do you query JSON data in Snowflake?
Using dot notation or the GET_PATH function on VARIANT columns.
What is Snowflake’s external table?
A table for querying data stored in external locations like S3 without loading it into Snowflake.
What is the difference between a VARIANT column and a relational column?
- VARIANT: Stores semi-structured data.
- Relational column: Stores structured data with defined data types.

How do you integrate Snowflake with ETL tools?
Using connectors like Snowflake Connector for Python, JDBC, or third-party tools.
How do you integrate Snowflake with BI tools?
Using drivers and connectors like ODBC or native integrations with Tableau, Power BI, etc.
What is Snowpipe?
A continuous data ingestion service in Snowflake.
How does Snowflake integrate with AWS?
Through services like S3, Lambda, and Redshift Spectrum.
What is the role of Snowflake’s REST API?
Allows programmatic access to Snowflake functionalities like queries and user management.

What is a shared database in Snowflake?
A database shared across Snowflake accounts without data duplication.
What is a transient table in Snowflake?
A temporary table that doesn’t support Time Travel.
What are tasks in Snowflake?
A feature for scheduling and automating SQL statements.
What is the difference between Snowflake Standard and Enterprise editions?
Enterprise edition includes advanced features like multi-cluster warehouses and Time Travel for up to 90 days.
How do you use streams in Snowflake?
Streams track data changes in a table for CDC (Change Data Capture).

How do you migrate data to Snowflake from an on-prem database?
Use tools like Snowflake Migration Assistant, Snowpipe, or third-party ETL tools.
How do you troubleshoot query performance in Snowflake?
- Use query history.
- Analyze query plans using EXPLAIN.
What happens if a virtual warehouse is overloaded?
Queries may queue unless another virtual warehouse is used.
How do you optimize Snowflake costs?
- Use auto-suspend for warehouses.
- Use compact storage formats.
- Optimize warehouse sizing.
What is a fail-safe in Snowflake?
A feature to recover data within 7 days after Time Travel retention expires.