Answer: Connect to Pool1 and DBCC PDW_SHOWSPACEUSED.

## Analysis of Data Skew Detection in Azure Synapse Analytics ### Understanding the Scenario - You have a **dedicated SQL pool** named Pool1 containing a fact table named Table1 - You need to identify **data skew** - the uneven distribution of data across distributions in a distributed table - The question specifically asks what to run **in Synapse Studio** ### Evaluation of Options **✅ Option A: Connect to Pool1 and run DBCC PDW_SHOWSPACEUSED** - **Optimal Choice**: This is the correct approach for dedicated SQL pools - **DBCC PDW_SHOWSPACEUSED** specifically shows space usage across all 60 distributions in Azure Synapse Analytics - It displays row counts and space usage per distribution, allowing you to identify uneven data distribution - Must be executed against the **dedicated pool (Pool1)** where the table resides - This command provides the most direct view of data distribution across distributions **❌ Option B: Connect to the built-in pool and run DBCC PDW_SHOWSPACEUSED** - **Incorrect**: The built-in pool refers to the serverless SQL pool, not the dedicated pool - DBCC PDW_SHOWSPACEUSED is not available in serverless pools - Cannot access tables in dedicated pools from serverless pools **❌ Option C: Connect to the built-in pool and run DBCC CHECKALLOC** - **Incorrect**: DBCC CHECKALLOC is for checking page allocation consistency, not data skew - This command verifies page allocation structures, not data distribution across nodes - Again, built-in pool cannot access dedicated pool tables **❌ Option D: Connect to the built-in pool and query sys.dm_pdw_sys_info** - **Incorrect**: sys.dm_pdw_sys_info provides system-level information about the SQL pool, not table-specific data distribution - This DMV shows appliance-level counters and system configuration, not data skew within specific tables - Built-in pool cannot query dedicated pool system views ### Key Technical Considerations - **Dedicated vs Built-in Pools**: Dedicated SQL pools (formerly SQL DW) use MPP architecture with data distributed across 60 distributions. Built-in pools are serverless and cannot access dedicated pool objects. - **Data Skew Detection**: The primary method for identifying data skew in dedicated pools is analyzing distribution-level statistics, which DBCC PDW_SHOWSPACEUSED provides. - **Best Practice**: For comprehensive analysis, you might later use sys.dm_pdw_nodes_db_partition_stats, but DBCC PDW_SHOWSPACEUSED is the quickest way to get an initial view of data distribution. ### Conclusion Option A is the only technically correct approach that connects to the appropriate pool and uses the proper command for identifying data skew in dedicated SQL pool tables.