What should you recommend?

You have the following query.

SELECT * FROM с

WHERE c.sensor = "TEMP1"

AND c.value < 22

AND c.timestamp >= 1619146031231

You need to recommend a composite index strategy that will minimize the request units (RUs) consumed by the query.

What should you recommend?
A . a composite index for (sensor ASC, value ASC) and a composite index for (sensor ASC, timestamp ASC)
B . a composite index for (sensor ASC, value ASC, timestamp ASC) and a composite index for (sensor DESC, value DESC, timestamp DESC)
C . a composite index for (value ASC, sensor ASC) and a composite index for (timestamp ASC, sensor ASC)
D . a composite index for (sensor ASC, value ASC, timestamp ASC)

View Answer

Answer: A

Explanation:

If a query has a filter with two or more properties, adding a composite index will improve performance.

Consider the following query:

SELECT * FROM c WHERE c.name = “Tim” and c.age > 18

In the absence of a composite index on (name ASC, and age ASC), we will utilize a range index for this query. We can improve the efficiency of this query by creating a composite index for name and age.

Queries with multiple equality filters and a maximum of one range filter (such as >,<, <=, >=, !=) will utilize the composite index.

Reference: https://azure.microsoft.com/en-us/blog/three-ways-to-leverage-composite-indexes-in-azure-cosmos-db/