MongoDB C100DBA Exam - Topic 1 Question 9 Discussion

Actual exam question for MongoDB's C100DBA exam

Question #: 9
Topic #: 1

Given a replica set with five data-bearing members, suppose the primary goes down with operations in its oplog that have been copied from the primary to only one secondary. Assuming no other problems occur, which of the following describes what is most likely to happen?

Amissing operations will need to be manually re-performed

Bthe secondary with the most current oplog will be elected primary

Creads will be stale until the primary comes back up

Dthe primary may roll back the operations once it recovers

Ethe most current secondary will roll back the operations following the election

Show Suggested Answer

Suggested Answer: B

by Carissa at May 09, 2022, 04:48 PM

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Ricarda

4 months ago

E seems off, I doubt the secondary will roll back anything.

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Amie

4 months ago

Wait, can the primary really roll back ops? Sounds risky!

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Johana

4 months ago

C makes sense too, reads will be stale for sure.

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Lenny

4 months ago

I think B is more likely, that secondary could become primary.

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Joana

5 months ago

A is definitely true, missing ops need to be redone.

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Crissy

5 months ago

I vaguely remember that if the primary recovers, it might roll back operations, but I’m not entirely certain how that interacts with the election process.

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Quiana

5 months ago

I practiced a similar question, and I feel like reads might be stale until the primary comes back up, but I can't recall the exact details.

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Daren

5 months ago

I remember something about how the oplog works, but I'm not sure if the secondary can just take over without issues.

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Tanesha

5 months ago

I think the secondary with the most current oplog will be elected primary, but I'm a bit confused about the rollback implications.

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Katie

5 months ago

The ability to use globals with decision tables is an interesting point, but I'm not sure if that's a significant advantage over if-then rules. I'll have to weigh the pros and cons of each approach.

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German

5 months ago

Okay, I've got this. The key is to use a lookup to filter the data and find the relevant information to resolve CustomerB's issue. Options A and B are the correct answers here.

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Sanda

5 months ago

Okay, I think I've got this. The key is to identify the reason the account is in this particular status, based on the information provided. Let me work through the options.

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Zita

5 months ago

I think I learned that `git checkout` is mostly for switching branches or restoring files, so that doesn't apply here. Not really sure about `git clean`, though.

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