Verifying the clustering key is being used by queries

Question
We recently completed a re-ingest of data that uses a clustering key. What is the best way to verify that the clustering key is being used by the queries? For example, if there’s a column_scan HINT, is the clustering field used?

Answer
After executing your query, you can use the Query Profiler under the Performance tab to see how many rows the column scan processed. It should be significantly less than the collection size which will indicate that clustering is working. Just keep in mind that the access has to be a column scan-- so be sure to verify you’re using that first and then check the row counts. You may want to use the column scan HINT if it is not being used already.

The clustering feature is used to improve when using column_scan as the access path.