Delta Tables in Unity Catalog - My Organization vs Unity Catalog - Legacy - Hive Metastore

Question

We have multiple Databricks Delta Tables that were created before Unity Catalog came into picture.  After Unity Catalog got included in our Project,  all our Tables are shown in Unity Catalog as part of Legacy.  We would like to know if having them as part of My Organization instead of Legacy have any benefits w.r.t Performance, Security etc..

Answer 1

Hi @Immaneni, Nanda

Greetings & Welcome to Microsoft Q&A forum! Thanks for posting your query!

Using Unity Catalog for managing your Delta Tables instead of relying on the legacy Hive metastore offers several benefits, particularly in terms of performance, security, data governance and management.

Basic Concepts:

Delta Tables - These are a type of table in Databricks that support ACID transactions, scalable metadata handling, and unifies streaming and batch data processing.

Unity Catalog - This is a unified governance solution for all data assets in Databricks. It provides a centralized way to manage data access, security, and auditing across various data sources.

Legacy Hive Metastore - This is the traditional metadata store used in many big data environments, including Databricks, before Unity Catalog was introduced. It manages metadata for tables and other data assets but lacks some of the advanced features of Unity Catalog.

We would like to know if having them as part of My Organization instead of Legacy have any benefits w.r.t Performance, Security etc..

Security:

Legacy (Hive Metastore) - Basic ACL-based access control with less flexibility. No native support for advanced security mechanisms like data masking or row-level filtering. Metadata is not inherently secure, risking exposure of sensitive information.

My Organization (Unity Catalog) - Fine-Grained Access Control: Table, column, row-level permissions, and data masking for PII compliance. Row-Level Filtering: Dynamically restricts access based on user attributes or roles. Comprehensive Auditing: Tracks every data access and modification for compliance monitoring.

Performance:

Legacy (Hive Metastore) - Can slow down with complex metadata structures (e.g., many tables or partitions). Query planning and optimization may lag compared to newer architectures.

My Organization (Unity Catalog) - Efficient Metadata Management: Unity Catalog handles metadata more effectively, enabling faster query planning. Improved Data Discovery: Enhances user productivity by enabling quick access to relevant datasets.

Data Governance:

Legacy (Hive Metastore) - Limited capabilities for metadata management and data discovery. No built-in lineage tracking, complicating compliance and debugging efforts. Data sharing is more cumbersome and less secure.

My Organization (Unity Catalog) - Centralized Metadata Management: Unified catalog for easier metadata management. Data Lineage Tracking: Automatic tracking of data origins, transformations, and usage. Delta Sharing: Seamless and secure sharing of data across teams or even external partners. Enhanced discoverability with tagging, descriptions, and search capabilities.

Simplified Management:

Legacy (Hive Metastore) - Permissions and metadata management are decentralized, creating complexity and inconsistency. Maintaining access control for large user bases or complex environments is challenging.

My Organization (Unity Catalog) - Centralized Administration: Streamlined management of metadata, access, and security through a single pane of glass. Unified Access Control: Centralized and intuitive permission management.

Summary:

Migrating Delta tables from "Legacy" to "My Organization" in Unity Catalog is not just a technical upgrade; it represents a strategic move towards enhanced security, improved performance, streamlined data governance, and simplified management.

By leveraging the advanced features of Unity Catalog, organizations can significantly improve their data management practices, ensuring that they are better equipped to handle the complexities of modern data environments while maintaining compliance and security.

For additional information, please refer: Unity Catalog vs. legacy Hive metastore

I hope this information helps. Please do let us know if you have any further queries.

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Thank you.