When would you usually consider to add clustering key to a table?

Question

Options

• AThe performance of the query has deteriorated over a period of time.
• BThe number of users querying the table has increased
• Cit is a multi-terabyte size table
• DThe table has more than 20 columns

• A
  79% (44)
• B
  14% (8)
• D
  7% (4)

Explanation

Clustering keys in Snowflake help optimize micro-partition pruning for large tables. Answer A is correct: when query performance degrades over time, it often indicates that data has been inserted in a non-clustered order, causing poor pruning efficiency - adding a clustering key triggers automatic reclustering to maintain data organization. Answer C is correct: clustering is most beneficial and cost-effective on multi-terabyte tables, where the overhead of maintaining the cluster is justified by significant pruning improvements. Answer B is incorrect: adding more users is a workload concurrency issue, not a clustering issue - scaling the warehouse or enabling multi-cluster warehouses addresses this. Answer D is incorrect: column count has no bearing on whether clustering is beneficial; the relevant factor is query filter selectivity on specific columns.

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