A financial services company needs to run ad-hoc SQL queries on petabytes of data stored in Azure Data Lake Storage without provisioning a dedicated data warehouse. Which Azure service should they use?
Serverless querying of data lake files.
Why this answer
Azure Synapse Analytics serverless SQL pool is the correct choice because it allows you to run ad-hoc SQL queries directly against data in Azure Data Lake Storage without provisioning any dedicated compute resources. It uses a pay-per-query model, automatically scaling compute to handle petabytes of data, making it ideal for intermittent, exploratory workloads.
Exam trap
The trap here is that candidates often confuse Azure Data Lake Storage (a storage service) with a query engine, or assume that a provisioned data warehouse like Azure SQL Database is required for any SQL workload, missing the serverless, on-demand nature of Synapse serverless SQL pool.
How to eliminate wrong answers
Option B is wrong because Azure Analysis Services is an OLAP engine for semantic models and pre-aggregated data, not designed for direct ad-hoc SQL queries on raw petabyte-scale data in Data Lake Storage. Option C is wrong because Azure SQL Database is a provisioned, transactional relational database with fixed storage limits, unsuitable for petabyte-scale data lake queries without prior data loading. Option D is wrong because Azure Data Lake Storage is a storage service, not a query engine; it provides the data layer but cannot execute SQL queries itself.