Optimize Query Performance COF-C03 Practice Questions (Page 4)

Questions 16–20

1. 16application · medium

   A data engineer notices that a nightly reporting query has become slower over the past week. Using the query profile in Snowsight, they see that the query spends 90% of its time in a single table scan step, and the number of micro-partitions scanned has increased significantly. The table is large and frequently filtered on a column that is not part of the primary key. Which action should the engineer take first to address the performance degradation?

   • AReview the query profile to confirm the scan is the bottleneck and check pruning statistics.
   • BIncrease the warehouse size.
   • CAdd a clustering key on the filter column.
   • DEnable search optimization on the table.
   Reveal Solution Discussion Select an answer first
2. 17foundation · easy

   What is a key characteristic of a materialized view in Snowflake?

   • AIt stores the precomputed results of a query and is automatically maintained
   • BIt is a copy of the base table that is manually refreshed
   • CIt is a virtual view that runs the query each time it is accessed
   • DIt is a temporary table that is dropped after the session ends
   Reveal Solution Discussion Select an answer first
4. 18foundation · easy

   When analyzing a slow query, which metric from the Query Profile would most directly indicate a bottleneck in scanning large amounts of data?

   • APercentage of data scanned from the table
   • BNumber of rows returned
   • CQuery compilation time
   • DWarehouse credit usage
   Reveal Solution Discussion Select an answer first
5. 19application · medium

   A query that joins three tables is running slower than expected. The query profile shows that the join order is suboptimal, with the largest table joined first. The team wants to improve performance by changing the join order. What should they do?

   • AUse a LEFT JOIN instead of an INNER JOIN.
   • BIncrease the warehouse size.
   • CRewrite the query to join the smallest table first.
   • DAdd a clustering key on the join columns.
   Reveal Solution Discussion Select an answer first
6. 20foundation · easy

   What is the main benefit of enabling the search optimization service on a Snowflake table?

   • AIt reduces storage costs by compressing the table
   • BIt automatically clusters the table for all queries
   • CIt improves performance of all aggregations
   • DIt accelerates point lookups and selective queries on the table
   Reveal Solution Discussion Select an answer first