Snowflake COF-C02 Exam - Topic 3 Question 60 Discussion

Actual exam question for Snowflake's COF-C02 exam

Question #: 60
Topic #: 3

[All COF-C02 Questions]

What happens to the underlying table data when a CLUSTER BY clause is added to a Snowflake table?

AData is hashed by the cluster key to facilitate fast searches for common data values

BLarger micro-partitions are created for common data values to reduce the number of partitions that must be scanned

CSmaller micro-partitions are created for common data values to allow for more parallelism

DData may be colocated by the cluster key within the micro-partitions to improve pruning performance

Show Suggested Answer

Suggested Answer: D

When aCLUSTER BYclause is added to a Snowflake table, it specifies one or more columns to organize the data within the table's micro-partitions. This clustering aims to colocate data with similar values in the same or adjacent micro-partitions. By doing so, it enhances the efficiency of query pruning, where the Snowflake query optimizer can skip over irrelevant micro-partitions that do not contain the data relevant to the query, thereby improving performance.

References:

Snowflake Documentation on Clustering Keys & Clustered Tables1.

Community discussions on how source data's ordering affects a table with a cluster key

by Merilyn at Aug 19, 2025, 12:48 AM

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Lenna

2 months ago

Wait, are we sure about B? Larger micro-partitions?

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Glenn

2 months ago

I think D makes more sense for pruning performance.

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Noe

2 months ago

A is correct! It helps with faster searches.

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Lili

3 months ago

Totally agree with D, colocating data is key!

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Celeste

3 months ago

I thought clustering just reorganized data, not hashed it.

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Fausto

3 months ago

I believe that clustering can help reduce the number of partitions scanned, so maybe option B is correct, but I’m not entirely confident.

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Ryan

3 months ago

I practiced a similar question, and I feel like the hashing aspect is important, but I can't recall if that's the main effect of CLUSTER BY.

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Kiley

4 months ago

I remember something about how data is colocated by the cluster key, which improves pruning performance. That sounds like option D to me.

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Billy

4 months ago

I think the CLUSTER BY clause helps with data organization, but I'm not sure if it actually creates larger or smaller micro-partitions.

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Pearlie

4 months ago

The CLUSTER BY clause is all about optimizing the micro-partitions, so I'm guessing it's either option B or C. I'll need to think through the tradeoffs a bit more to decide.

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Karl

4 months ago

I'm pretty confident that the CLUSTER BY clause is about hashing the data to facilitate faster searches. I think option A is the right answer here.

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Danica

4 months ago

Based on the options, it seems like the CLUSTER BY clause helps with data pruning and parallelism. I'm leaning towards option D, since that sounds the most relevant.

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Emeline

5 months ago

Hmm, I'm a bit confused on the exact impact of the CLUSTER BY clause. Is it just about creating larger or smaller micro-partitions, or is there more to it?

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Ozell

5 months ago

I think the key here is understanding how Snowflake's micro-partitioning works. The CLUSTER BY clause should help group common data values together to improve query performance.

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