The DBCC PDW_SHOWSPACEUSED command in Azure Synapse Analytics dedicated SQL pool reveals how data is distributed across the compute nodes. When examining the results, if some distributions show significantly more data than others (or some distributions have no data at all), this indicates data skew. Data skew occurs when the distribution key chosen for the table does not evenly distribute data across all distributions, leading to some nodes handling more data and processing than others. This can negatively impact query performance as workloads become unbalanced.

• Option A (All distributions contain data): This is incorrect because the results clearly show that not all distributions contain data—some have zero rows, which is evidence of skew.
• Option B (The table contains less than 10,000 rows): This is not necessarily true and cannot be determined solely from the presence of skew; the total row count could be higher or lower, but skew is about uneven distribution, not total size.
• Option C (The table uses round-robin distribution): Round-robin distribution aims to evenly distribute data across all distributions. The observed skew indicates that round-robin is likely not being used; instead, a hash distribution key is probably causing the imbalance.
• Option D (The table is skewed): This is correct, as the uneven data distribution across distributions directly indicates skew, which is a common performance concern in distributed systems like dedicated SQL pools.