Which database feature provides recommendations for indexing based on query performance?

The feature that provides recommendations for indexing based on query performance is Automatic Tuning. This functionality in Azure SQL Database and SQL Server is designed to analyze workloads and identify performance issues, including those related to indexing. When Automatic Tuning is enabled, it can suggest and apply index recommendations automatically, helping to optimize query performance without requiring manual intervention by the database administrator.

Automatic Tuning continuously monitors the database and can take actions such as creating missing indexes or dropping unused indexes, which is crucial in maintaining optimal performance as workloads change over time. This feature assists administrators by taking advantage of machine learning algorithms that assess which indexes would provide the most benefit for the current query patterns.

The other options, while helpful for performance monitoring and analysis, do not provide automatic recommendations for indexing improvements directly based on query performance. For example, SQL Query Store is primarily focused on capturing query performance statistics over time. SQL Server Profiler is a tool for tracing events and capturing detailed information about database activity, which can inform decisions but does not provide automated indexing recommendations. Dynamic Management Views offer insights into the current state of the SQL Server instance and its databases, but they require a manual interpretation to draw conclusions regarding indexing.