Establishing a global indexing and metadata layer is pivotal in a federated lakehouse architecture for seamless access and query performance across disparate data domains. This layer abstracts the physical storage details, offering a unified querying interface without the need for knowledge about the data's physical location or format. It centralizes data access management, optimizes query performance by simplifying access to variously stored data, and provides insights into the data landscape for better query execution planning. This approach is ideal for maintaining efficiency and performance in cross-domain analytics.