Best Practices for Metadata Refresh Frequency in Dremio

This guide provides best practices for setting and adjusting metadata refresh frequencies for datasets in Dremio. It begins by defining metadata and explaining its importance in query validation and execution efficiency. The document details how Dremio automatically collects metadata upon dataset promotion and the implications of stale metadata on query performance. It outlines the inline metadata refresh process and the specific requirements for Iceberg and Delta Lake tables regarding metadata updates. Recommendations for adjusting refresh frequencies are provided, emphasizing the need for alignment with data ingestion rates. The guide also discusses the scheduling of metadata refreshes at the data source level, advising against overly frequent refreshes that do not match data update frequencies. Additionally, it covers on-demand refresh strategies and the use of dedicated engines for metadata refresh tasks to optimize resource utilization. Overall, the document serves as a comprehensive resource for managing metadata refresh in Dremio effectively.