Azure Synapse Analytics: Introduction to Metadata Activity [Introduction to Synapse - Ep. 11]

This blog post summarizes the key points from Mitchell Pearson’s video on Get Metadata Activity in Azure Synapse Analytics. This activity is essential for building dynamic, data-driven pipelines and understanding how to reference outputs effectively.

Overview

The Get Metadata Activity is a powerful tool within Synapse pipelines that allows developers to retrieve metadata about files, tables, or other resources. It is commonly used for dynamic workflows, validation, and automation.

Why Use Get Metadata Activity?

• Dynamic Pipelines: Enables automation by checking file existence and retrieving properties before processing.
• Validation: Helps confirm file attributes like size or last modified date for ETL processes.
• Control Flow: Supports conditional logic and iterative workflows using metadata outputs.

Key Features and Options

1. Existence Check: Verify if a file exists before processing.
2. Last Modified Date: Compare timestamps to determine if a file is new or updated.
3. Item Name and Type: Retrieve file names and types for dynamic looping scenarios.
4. Size: Validate file size for quality checks.

Step-by-Step Setup

1. Create or select an existing dataset linked to your Data Lake.
2. Add the Get Metadata Activity to your pipeline from the General category.
3. Configure required settings:
   • Select the dataset.
4. Run in Debug Mode to view outputs before publishing.

Understanding Outputs

The output is returned in JSON format, making it easy to reference in subsequent activities. For example:

@activity('GetMetadata1').output.lastModified
@activity('GetMetadata1').output.exist
        

These expressions can be used in conditional activities like Until or ForEach loops to control pipeline execution dynamically.

Best Practices

• Use debug runs for quick validation before publishing changes.
• Combine metadata checks with control tables for robust ETL workflows.
• Leverage dynamic content expressions for flexible pipeline logic.

Conclusion

The Get Metadata Activity is one of the foundational tools in Synapse pipelines. It teaches developers how to work with dynamic content and reference outputs effectively. Mastering this activity opens the door to building scalable, automated data solutions.

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