Analysis of Folder Structure Options

Key Requirements:

• Supports usage patterns: Most queries filter by current year OR week
• Simplifies folder security: Data secured by data source
• Minimizes query times: Optimized for year/week filtering

Evaluation of Options:

Option A (\DataSource\SubjectArea\YYYY\WW\FileData_YYYY_MM_DD.parquet) - RECOMMENDED

• Security: Places data source at the top level, enabling straightforward security policies at the data source level
• Query Performance: Hierarchical structure (YYYY→WW) allows efficient partition pruning when filtering by year, and still supports week filtering through folder traversal
• Usage Pattern Support: Organizes data logically by time granularity, supporting both year-based and week-based queries
• Best Practice: Follows Azure's recommended hierarchical partitioning approach

Option B (\DataSource\SubjectArea\YYYY-WW\FileData_YYYY_MM_DD.parquet) - NOT OPTIMAL

• Query Performance: Combines year and week in single folder name, requiring full folder scan when filtering by week alone
• Security: Similar to A, but query optimization is compromised
• Usage Pattern: Less efficient for "year OR week" filtering requirement

Option C (DataSource\SubjectArea\WW\YYYY\FileData_YYYY_MM_DD.parquet) - NOT OPTIMAL

• Security: Data source not at top level, complicating security implementation
• Query Performance: Week-first hierarchy is inefficient for year-based queries

Option D (\YYYY\WW\DataSource\SubjectArea\FileData_YYYY_MM_DD.parquet) - NOT OPTIMAL

• Security: Data source buried deep in hierarchy, making security management complex
• Query Performance: Time-based partitioning is good, but security requirement is compromised

Option E (WW\YYYY\SubjectArea\DataSource\FileData_YYYY_MM_DD.parquet) - NOT OPTIMAL

• Security: Worst option for security implementation with data source at bottom
• Query Performance: Week-first hierarchy is inefficient

Why Option A is Optimal:

1. Security Simplification: Data source at root level enables straightforward access control policies
2. Query Optimization: Hierarchical time partitioning (Year→Week) enables efficient partition elimination
3. Usage Pattern Alignment: Supports both year-based and week-based filtering scenarios
4. Azure Best Practices: Aligns with Microsoft's recommended data lake organization patterns for time-series data

Option A provides the best balance of security management simplicity and query performance optimization while fully supporting the specified usage patterns.