HOTSPOT -
You have an Azure Cosmos DB Core (SQL) API account named account1.
In account1, you run the following query in a container that contains 100GB of data.
You view the following metrics while performing the query.
For each of the following statements, select Yes if the statement is true. Otherwise, select No.
NOTE: Each correct selection is worth one point.
Hot Area:
Box 1: No -
Each physical partition should have its own index, but since no index is used, the query is not cross-partition.
Box 2: No -
Index utilization is 0% and Index Look up time is also zero.
Box 3: Yes -
A partition key index will be created, and the query will perform across the partitions.
Reference:
https://docs.microsoft.com/en-us/azure/cosmos-db/sql/how-to-query-container
YNY "This query's filter uses the system function UPPER, which isn't served from the index." https://learn.microsoft.com/en-us/azure/cosmos-db/nosql/query-metrics-performance#scan-queries-commonly-slow-and-expensive
YNN < correction
This is the correct answer
This is the correct answer
To correctly answer the question one would have to know the partionkey https://learn.microsoft.com/en-us/azure/cosmos-db/nosql/how-to-query-container
using a function like Lower on the left side of equality won't use the index in relational dbs. Not sure about Cosmosdb
how do we know if it's cross partition query or not?
The third question ask waht happens when the container is recreated with the customerid as partition key, so it is not currently the partition key, therfore the query is cross partition.
I would say YNY
YNN When you apply the LOWER() function to c.categoryid, the query engine cannot determine the exact value of the partition key without evaluating the function. As a result, Cosmos DB cannot route the query to a specific partition and must perform a cross-partition query, which can be less efficient.