Discuss Microsoft DP-420 Exam Topic 3 Question 4

You have the following query.

SELECT * FROM

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?

Aa composite index for (sensor ASC, value ASC) and a composite index for (sensor ASC, timestamp ASC)

Ba composite index for (sensor ASC, value ASC, timestamp ASC) and a composite index for (sensor DESC, value DESC, timestamp DESC)

Ca composite index for (value ASC, sensor ASC) and a composite index for (timestamp ASC, sensor ASC)

Da composite index for (sensor ASC, value ASC, timestamp ASC)

Suggested Answer: A

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.

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11 comments · newest first

Demetra 12 months ago

Wait, why would we need two different index directions? That seems odd.

Sylvia 1 year ago

B seems overkill with both ASC and DESC indexes.

Lorean 1 year ago

Not so sure about D, what if the timestamp isn't as relevant?

Catalina 1 year ago

Totally agree, D covers all the bases!

Peggy 1 year ago

I think option D is the best choice for this query.

Nieves 1 year ago

I’m a bit confused about the timestamp part. Should it be included in the index if it’s only used for filtering?

Justine 1 year ago

I practiced a similar question where the order of columns in the index really mattered. I think option D might be the best choice here.

Blossom 1 year ago

I think we need to focus on the order of the fields in the index. The sensor is a key filter, right?

Ruth 1 year ago

I'm not entirely sure, but I remember something about composite indexes needing to match the query's filter conditions closely.

Lura 1 year ago

I'm a little unsure about the differences between some of these options. I'll need to double-check the ZFS documentation to make sure I understand the implications of each one.

Brett 1 year ago

Okay, let me break this down step-by-step. I think the key is understanding what "tag along rights" are in the context of a Buy-Sell agreement.

Microsoft DP-420 Exam - Topic 3 Question 4 Discussion