Snowflake ADA-C01 Exam - Topic 7 Question 7 Discussion

Actual exam question for Snowflake's ADA-C01 exam

Question #: 7
Topic #: 7

What is a characteristic of Snowflake's transaction locking and concurrency modeling?

AA deadlock cannot occur in Snowflake, since concurrently executed queries and DML statements do not block one another.

BIf two queries are concurrently executed against the same table, one of the two queries will be blocked until the other query completes.

CTransaction locking in Snowflake is enforced exclusively at the row and table levels.

DQueries executed within a given transaction see that transaction's uncommitted changes.

Show Suggested Answer

Suggested Answer: A

According to the Snowflake documentation1, Snowflake uses a multi-version concurrency control (MVCC) model, which means that each transaction operates on a consistent snapshot of the database at a point in time. This allows queries and DML statements to run concurrently without blocking each other, as they do not modify the same data. Therefore, a deadlock, which occurs when concurrent transactions are waiting on resources that are locked by each other, cannot happen in Snowflake. Option B is incorrect because queries and DML statements do not block each other in Snowflake, unless they are explicitly started transactions and multiple statements in each transaction2. Option C is incorrect because transaction locking in Snowflake is enforced at the partition level, not the row or table level3. Option D is incorrect because queries executed within a given transaction do not see that transaction's uncommitted changes, but only the committed changes that occurred before the transaction started1.

by Jettie at Feb 07, 2024, 06:02 AM

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Buddy

3 months ago

I heard the same, no blocking means better performance!

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Roxane

3 months ago

Wait, are you sure about that? Sounds too good to be true.

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Chantell

3 months ago

Definitely agree, concurrency is a strong point for Snowflake.

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Veronika

4 months ago

I thought queries could block each other, but I guess not!

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Arlene

4 months ago

A deadlock can't happen in Snowflake, that's pretty cool!

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Francesco

4 months ago

I think D sounds familiar because I remember discussing how transactions in Snowflake can see uncommitted changes, but I'm not 100% confident about it.

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Becky

4 months ago

I vaguely recall something about transaction locking being more flexible in Snowflake, but I can't remember if it was just at the row and table levels or something else. C seems a bit off to me.

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Nana

4 months ago

I'm not entirely sure, but I feel like I came across a practice question that mentioned queries being blocked if they were trying to access the same data. That makes me lean towards B.

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Tori

5 months ago

I remember studying that Snowflake's architecture allows for concurrent queries without blocking, so I think A might be correct.

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Rosina

5 months ago

I've studied this topic before, and I'm pretty confident the answer is A. Snowflake's isolation level and concurrency control mechanisms are designed to prevent deadlocks and allow concurrent queries to execute without blocking.

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Miles

5 months ago

Okay, let me see if I can break this down. I think the key is understanding Snowflake's transaction locking model. Option C sounds plausible, but I'm not 100% sure.

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Maile

5 months ago

Hmm, I'm a bit confused on this one. I know Snowflake has some unique concurrency features, but I can't quite remember the details. I'll have to think this through carefully.

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Reena

5 months ago

I'm pretty sure the answer is A. Snowflake's architecture is designed to avoid deadlocks, so concurrent queries shouldn't block each other.

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Lynelle

5 months ago

This question seems straightforward. I think the answer is Computer Forensic Investigator, as that title best describes the responsibilities outlined in the question.

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Tish

5 months ago

Okay, let's see. I think option B might be the way to go here, but I'm not 100% sure.

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Tayna

5 months ago

Okay, let me think this through step-by-step. The report shows summary statistics for the Age variable, so I need to look for the option that uses the Age variable correctly in the PROC MEANS statement.

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Alberta

5 months ago

I feel like going through the GUI might not help much for CLI-specific issues, but I'm not completely confident in this one.

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Leonard

5 months ago

Hmm, I'm a bit unsure about this one. I'll need to review the details more closely and make sure I understand the full context before deciding.

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Bonita

5 months ago

Okay, let me see. The support staff in Mintzberg's model provide indirect support to the organization, so I'm guessing it's not the line supervisors or the accountants. HR managers or press relations staff seem like the most likely options here.

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